Breast pain in one breast, sharp?

Yesterday morning I noticed when my boyfriend hugged me that I had a sharp pain in chest, I soon found out it was actually coming from my breast, my left one, near the nipple (on the side close to chest). There are no other symptoms or lumps at all, and I don't see how I would've had an injury... it feels tender, like a bruise, or touching somewhere that has gotten injured. It only hurts when it is pressed, although if I massage it, it doesn't always hurt, only usually if there is a sudden press.

I am only 22, no family history of anything let alone breast cancer, eat really well, exercise, not remotely overweight, don't drink or smoke, etc. I know it can happen to anyone but I'm sure it's something else, any ideas?

I am not on Pill, I was on it for six months but came off it 2 or 3 weeks ago, my period isn't due for almost 2 weeks. I am definitely not pregnant.

I am going to doctor tomorrow just to check it's all ok, of course, so please don't just reply telling me to do that!

Oh, and it seems to be definitely breast tissue, not ribs or breastbone or muscle.

It could be a engorged milk duct. They sometimes form around the time of your period - though not always- and can be extremely painful when hugged, or when laying on your stomach, etc.

They usually go away on their own after a few weeks but you should monitor it to see if it grows into a lump/ bump.

Hope this helps.