If you're a female of menstruating age and you don't know what pre-period breast pain feels like, then go and buy a lottery ticket immediately. You're obviously a) extremely lucky and b) a member of the minority.
For the rest of us, that pulsating, tender, heavy feeling is all too familiar, and it's the pits.
So why exactly do your normally friendly boobs turn into your worst enemies at a certain time of the month? And is there anything you can do to get some relief?
As with pretty much everything to do with your period, breast pain all comes down to hormones, Dr Judith Reddrop of Women’s Wellbeing told The Huffington Post Australia.
"It's all due to hormonal fluxes in the menstrual cycle," Reddrop said. "Estrogen reaches a peak around the middle of your cycle, and progesterone reaches its peak the following week.
"As it turns out, both are at very high levels during the second half of your cycle. It's like a hormone party in your breasts.
"On top of that, breasts are particularly affected because they have estrogen and progesterone receptors, so they are especially picked on in that way."
If you're wondering exactly how progesterone and estrogen affect your boobs (as if you didn't know already), they can make them swell, become congested, feel tender and, for some women, cause lumpiness.
"It's not comfortable but there's a good biological reason for that happening, and it shows your hormones are working particularly efficiently," Reddrop said.
In terms of actions you can take to minimise discomfort, Reddrop says there are plenty of things you can do (aside from clutching a hot water bottle to your chest and eating Ben and Jerry's out of the tub, though that's good too).
"There are lots of lifestyle things you can do which really help. Obvious things, like having a well fitting bra or, if you're exercising, a good sports bra, are very important.
"What a lot of people don't know is exercising the week before your period actually seems to help. Also, avoiding caffeine, as it tends to aggravate the symptoms.
"If there's too much salt in your diet, this can lead to fluid retention which only makes the congestion feel worse."
In terms of remedies, Reddrop recommends vitamins B1 and B6 (50 - 100 mg per day) as well as evening primrose oil, which she suggests particularly bad PMS sufferers take throughout the entirety of the cycle.
"Vitamins B1 and B6 are involved in the hormonal pathways that manufacture your sex hormones, so they are known to help," Reddrop told HuffPost Australia.
"Evening primrose oil works best if you take it continuously (recommended dosage: 1000 - 2000 mg per day) which might seem like a bother, but some people who get real problems might be motivated to do that.
"When you're actually sore, Panadol or Nurofen or other anti-inflammatory medications can prove useful.
"Or, if your symptoms are particularly bad, you might want to consult a medical practitioner about the possibility of going on the contraceptive pill, which obviously stops ovulation and helps to give you stable and continuous hormones.
"That is quite a drastic measure but in some cases, ladies really need that additional help."
As a final point, Reddrop states breast lumpiness prior to your period is generally nothing to be worried about, but if you're concerned, it's best to check your breasts after your period has ended.
"The thing with sore breasts is, once the period starts, you'll find there is quite swift relief of the soreness and congestion," Reddrop said.
"The best time to check your breasts [for lumps] is after the period has finished, when the breasts are at their quietest.
"I wouldn't recommend conducting a breast check in the pre-menstrual time, because the breasts are having that hormone party they can feel quite lumpy. Don’t be alarmed. Just wait til the period is gone and check them then.
"Of course anything unusual, such as bleeding from nipple or discharge, any changes like that will mean you need to see your doctor as soon as possible."