I am feeling pain on my left side of my back very close to my stomach i can't bend my back for long what could be the problem?

Back pain: It's best that you see your FamilyDoc for an evaluation (or chat w/someone here) b/c we usually think of stomach as middle of abdomen below ribs & above belly button, not to one side or other. Perhaps you're referring to flank when you said "very close to my stomach), which would make me think of kidney stones or infection, although inability to bend makes me think of muscle strain.