<s>[INST] hello i belive i have a fat lump of gynoclomastia in my left pec (im a guy) i workout frrquently but have been out for a couple months and just got back, tonight after my shower i flexed my chest and literaly my inner lower pec just dissapeired! it looks weird but i also feel the out side of my pec where it enters the rotator cuff to crap, could this be the cause of my lower pec just missing like that, or the gyno or something? it feaked me out and is very displeasing to see. [/INST] Hi, dairy have gone through your question. I can understand your concern. You may have gynecomastia or lipoma or other mass.  You should go for ultrasound examination and fine needle aspiration cytology or biopsy of that lump. It will give you exact diagnosis. Then you should take treatment accordingly. Hope I have answered your question, if you have doubt then I will be happy to answer. Thanks for using Chat Doctor. Wish you a very good health. </s>