The last week or so I've been having a sharp pain when I exert myself too much (bench press, preacher curl, pull ups) like after the 5 or 6th rep it occurs. Then as i stop it goes away after a min or so. I get back to exerting and it comes back. If I lower the weight and intensity I don't get it. I noticed the protein shake with creatine and grass supplements I've been taking does make me burpy so at first I thought it was just the gasses but it only happens when I'm really stressing my body/muscles and it's been hot at my home gym (79/80F deg). Anyone else experience something similar? I just had my annual checkup (haven't done the blood test yet) but bp, heart, lungs etc all were normal. Although those tests are very basic in nature.