9 reasons you're finding sex painful.

Image: New Girl (Fox).

Sometimes sex can, in the hallowed words of John Mellancamp, hurt so good.

Other times, sex can hurt in an ‘oh God make it stop right now’ kind of way, which isn’t so good. When penetration causes you stinging pain, all the other positives of sex — the fun, the hilarity, the intimacy — can be overshadowed quickly.

“For any normal couple, sex can be a little bit painful sometimes, that might be because people jump in a little too quickly, there’s not enough lubrication, they go a bit more hard and fast than they normally would, it might be a new position, or the woman might be stressed so there can be muscle tension in the pelvic floor,” Sydney GP Dr Sam Hay explains.

RELATED: This is the number 1 most common sex injury

“Those things can come and go or occur once or twice, and that’s completely normal. It’s when you’re getting those problems continually, most or all of the time, or you notice a change … you might want to look into whether there’s an underlying problem.”

Here are nine of the most common causes of painful sex.

1. Not enough foreplay

We know you know foreplay is important to get everyone in the mood, but you mightn't realise just how vital it is in physically preparing your vagina for comfortable penetration.

RELATED: 8 unexpected ways to amp up your sex life.

"When we get properly stimulated, messages go to our brains to say, 'Hey, we need some space for a penis to enter in here'. There is a tilting of the uterus - it comes a bit straighter up on top of the vaginal canal, because it needs to take in sperm, and creates a little more room in the vaginal canal. There's also a secretion that occurs to allow a penis to go in and out without hurting us," relationship expert and sexologist Dr Nikki Goldstein explains. (Post continues after gallery.)

Thus, if you skip foreplay or struggle with it in a psychological sense, sex could hurt — either due to friction in your vaginal canal or through the tip of your partner's penis striking the opening of your cervix (seriously, ouch). "Unless that tilting and that space has occurred through foreplay and stimulation, sex can be painful. You can't just stick a penis in there and expect it'll all fit quite nicely," Dr Goldstein says.

2. Irritation or allergies

Genital irritation during sex might indicate an allergy or sensitivity to ingredients in certain lubricants, sex toys, spermicides or condoms. You might also be experiencing some irritation resulting from soaps and shampoos you've been using in the shower recently.

RELATED: 9 things all women need to know about cleaning their vagina.

It's also possible to be allergic to sperm, although that's rare. "I swear I've seen a patient with this; she gets significant allergy-like symptoms when her partner ejaculates inside her," Dr Hay says. "I have read about it and it does happen."

3. Size can matter

It's no secret vaginas can stretch to many times their size — the whole 'watermelon through a keyhole' thing (i.e. childbirth) serves as proof. So really, with the right preparation, accommodating a penis of just about any size should be achievable.

However, Dr Goldstein says this is more difficult for certain couples. "Say you have somebody who is very large, and someone who has a shorter vaginal canal, and there is a lack of foreplay or there is generally a lack of space, hitting the entrance to the cervix can be quite uncomfortable," she explains.

4. Vaginismus

Some women live with a condition called vaginismus: the involuntary clamping of the muscles in the pelvic region when any kind of penetration is imminent — that might be a penis, a tampon, or a pap smear. In many cases, vaginismus is a result of psychological factors. This might be the memory of trauma — a painful first experience with sex, or a history of sexual abuse — or negative beliefs associated with sex, like the idea that it's dirty or shameful, which then inform the pelvic muscles.

RELATED: Would you have sex for science?

Treatment of the condition can be complicated, because the specialist required largely depends on the cause. "If the cause is psychological, the obvious solution would be discussing the trauma with a sex therapist, but there's also a range of medical things that might be causing the muscles to spasm," Dr Goldstein says.

5. Emotional factors

Painful sex isn't necessarily a result of physical issues. "There's an underestimated link with emotional factors — stress, depression, or past experiences; like past painful sex, or maybe even past traumatic sex ... So they might find sex painful after that because there's a psychological association with it, and that can lead to a lot of pelvic floor tension and tightness," Dr Hay says.

6. Infection

Unsurprisingly, any infection in your reproductive region can make things a bit sore — this includes yeast infections or sexually transmitted infections like chlamydia, genital herpes or gonorrhoea.

There's also a common infection you might be less familiar with, called Pelvic Inflammatory Disease, which occurs when an infection in the vagina spreads to the cervix and fallopian tubes. "It's one thing a lot of women do seem to suffer from that they're not aware of. This can be an infection from an STI, or can be various infections that have happened in that lower region," Dr Goldstein says.

7. Underlying medical conditions

Existing medical conditions in your reproductive organs or the surrounding area, including Polycystic Ovarian Syndrome, Endometriosis and Adenomyosis, can also make sex uncomfortable. Vulvodynia is another potential source of sting.

8. Lower bowel issues

Infections and diseases in your lower bowel, like Irritable Bowel Syndrome, Crohn's disease, colitis or even severe bloating can also be a catalyst for pain.

"During penetration, if there's very lower pain it can get confusing — 'Is this to do with my vulva area or my very lower bowel?' If there's something wrong there that can cause sex to be very painful because you're disrupting or hitting that area," Dr Goldstein says.

RELATED: “The free, natural way I treat my IBS”

9. Menopause

The hormonal changes associated with menopause can significantly impact the vagina's natural lubrication, and also a woman's desire for sex.

So what now?

First of all, don't freak out. It's important to stop, take a step back and consider what might be contributing to your pain and how you can tackle it.

"I think the answer is to look at those simple things — are they not lubricated? In that case, spend more time with foreplay or use lube. Are they stressed or pissed off with the world, and need to relax a bit more? Then, put more emphasis on the enjoyment of sex, rather than the act of penetration," Dr Hay says.

Of course, some sources will pain will require medical attention. There are certain signs to keep an eye out for.

RELATED: “Why do I bleed during sex?”

"If there's blood, that would indicate a deeper infection or some trauma to the cervix internally," Dr Hay says. "If the pain is coming with a change in periods, whether that be heavier, lighter, more pain, or period-type pain, that would be a more alarming sign for us. From our point of view we're looking at ovarian problems, uterine problems, cervix problems, hormone problems that are influencing the cycle, and infection."

Interestingly, Dr Hay adds that muscular tension and trauma in the pelvic floor, such as childbirth, can be amenable to specific physiotherapy techniques. "I've only been made aware of this recently ... they use special massage techniques, special stretching, special pelvic floor exercises that make a massive difference," he says.

Have you ever experienced painful sex?

Dr Nikki Goldstein (right) is a Sydney-based Sexologist and Relationship Expert. You can also follow her on Twitter, Facebook and Instagram