Hi, I too have this symptom and occurs in my left breast only. I am 37 yrs old and have breastfed 3 children. I noticed the shooting pain started happening about 12 months ago and more so it seemed to happen around my monthly cycle. Not long after this, one day in the shower I was doing an examination and came across a lump. It feels long and soft, almost like a sausage! I was so scared. I immediately booked into the doctor and he diagnosed a fibroid. He said it was common in women in their thirties upwards. For reassurance he sent me for an ultrasound and it came back clear. Most terrifyingly in the last few weeks my own mum has been diagnosed with breast cancer and my breast pain has been at a peak (possibly due to stress?!!!!). Anyway, as you can imagine my anxiety levels were up there again. I had a mammogram and ultrasound a few days ago and they have once again come back clear. I will continue to have these checks every 12 months!