Sore, painful, or tender-to-the-touch breasts can be downright annoying. Although it may not make you feel any better, the good news is that, in most cases, sore breasts are nothing to fret about. Here are six possible reasons why your boobs hurt:

You’re premenstrual. Breast soreness is an incredibly common premenstrual symptom that’s brought on by hormonal fluctuations, according to Alyssa Dweck, an OB-GYN at the Mount Kisco Medical Group in NY, and co-author of V is for Vagina.

“The telltale sign is that the soreness is usually in both breasts,” Dweck told YouBeauty. “If you mark the symptoms on a calendar along with your period, it’s painfully obvious that it happens at the same time every month and resolves very abruptly once you get your period.”

You’re pregnant. If you’re of reproductive age and are either not using contraception every single time you have sex or are not using it correctly, it should come as no surprise that you may be pregnant. “If you have sore, full, swollen-feeling breasts and are not using contraception, you have to think pregnancy because that’s one of the first symptoms that comes about,” said Dweck. Your next move: Take a home pregnancy test or better yet, see your primary care physician for a blood test to confirm a possible pregnancy.

You have fibrocystic breasts. This common condition, characterized by having benign lumpy breast tissue, affects up to half of women at some point during their lives and typically shows up between ages 20 and 45. Fibrocystic breasts can feel full, swollen or even painful, particularly right before your period starts. “Women with fibrocystic breasts who are big caffeine drinkers may notice more soreness, so some patients who are nervous about the pain try diminishing their caffeine intake for a month or two to see if the pain goes away,” said Dweck. A supportive bra also helps.

You have a breast infection. If you’re breastfeeding your baby, there’s a potential for developing a breast infection called mastitis, which can cause a lot of pain and usually goes along with other symptoms of infection, such as redness, swelling, fever and chills. However, “getting a breast infection if you’re not nursing can sometimes be a red flag that something unusual is going on, such as a type of cancer,” said Dweck. Either way, see your primary care physician for an exam. If it’s mastitis, the condition is typically treated with antibiotics.

Your muscles are sore. What feels like breast tenderness may actually be sore muscle underneath your breasts. “If you’re trying a new workout program and weight training the pectoral muscles you may think it’s breast pain, but it’s musculoskeletal pain,” said Dweck. Try massaging the area and taking an over-the-counter pain reliever. The soreness should subside in two or three days.

Your bra doesn’t fit. Wearing an unsupportive bra when you workout (or even just walking around on a daily basis) can cause trauma to the breast tissue. Find a sports bra that holds your girls in place, and see a professional bra fitter to make sure you’re wearing the right size and getting the support your breasts need.

Not sure if your breast pain is worth bothering your doctor about? When it doubt, get it checked out. “If breast soreness or pain isn’t caused by something obvious that goes away in a reasonable period of time, you absolutely have to bring it up with your doctor,” said Dweck. “Anything that’s persistent, unusual, or causing anxiety, there’s no reason not to bring it up.”