its the only thing i can think of that might have caused my back to be excrutiatinly sore and stiff this morning. my cousin showed us his wii and we were playing that boxing game and i was throwing alot of punches and i was suprised how much i was sweating and how my energy got drained after about 5 mins of it. this morninig when i woke up, i felt sore in my upper back around my shoulder blade/shoulder area. i dont think it was from lifting on friday because i was fine saturday and sunday but i thought that that was odd. any other possible causes? with my sore back would it be a good idea to lift tonight or will it be fine? ill probably lift anyway though.