I was doing my first lifting exercise tonight with 12 lb dumbells and I got this stinging, burning pain in my upper back - like a really bad bee sting. It shocked me enough to make me immediately put down my dumbells and see if an insect actually had stung me. Nothing. I finished my workout and then lifted a heavy box. Bee sting pain again. Ouchie! Anyone know what I should do? Heating pad? Ice pack?