Im 17 and really fit and muscular for my age ! I worked olut at the gym today . Did back workout everything went fine . When i got back home i touched my chest and noticed a big bump on my left pec , i removed my shirt and a big part of my left pec was sticking out and looked swallen and fluidy that was the area between my niple and the pec side towards my left arm and going up a bit ! It s only noticable when i flexx and if i aply pressure it s gone but high pressure ( thats why i think it s noticable ) ( pressure = pushing it in with my right arm !) . If i turn my hand facing upward and holding the back of my head and flex i cant notice it and i think it is moving like if a part of the muscle is swallen or the fluid is moving upwaards if i move my hands up . Should i contineou working out at the gym or stop untill it s gone and will it ever go away . Also a note : my pecs where tired even from the 2nd movement ( second excersise out of 5 for back ) and they were shaking as in touching my knees with my elbows and watching my shirt shake from my pecs !