I have numbness when i bend my back backwards on the mid area under ribcage on my back and it goes around to front of ribcage.

Thoracic disc: A symptomatic thoracic disc rupture is rare but so are your symptoms. The only other common thing I can think of is early shingles. The later would quickly show a painful red blistered rash. The disc, at this point is only annoying an should stay that way. An MRI would diagnose the rupture or show even rarer lesions even less likely at your age.