<s>[INST] Hi, I am 16 years old, Five foot three, and weigh 125 pounds.  I exercise regularly.  The other day i was going for a run and I noticed I was quickly out of breath which isnt normal for me because I am an athlete.  My side was in a lot of pain.  When I got home I noticed that there is a large lump with a large amount of pain when I press upon it and also just in general right on my left rib cage, under my left breast.  There are no signs of breast cancer in my family. It hurts when I mover certain ways, exercise, laugh, and even breathe.  Also, it has made it harder for me to breathe in general.  I was wondering what this could be? [/INST] Hi, Dear,Thanks for the query from you to my Chat Doctor Clinic. I have gone through your query and appreciate your concerns of it. After in-depth study on it, In My opinion-the catchy breath holding with lump on left rib cage under the left breast, mostly could be-fibroadenosis, / or could be Viral fibromyalgia with pleuritic pain on inspiration.It's not a cancer for sure. Treatment -with Ghana and physician doctor-by Tb NSAIDs, and cold compresses, would resolve the pain soon. Any hormonal correction if need be would be given from GAEC doctor. Treament on above lines would relieve the issue. Hope this would resolve your worrisome query for now. Wellcome-to my Chat Doctor Clinic for any more query. </s>