Sharp pain in my spine, comes for a few seconds and then disappears?

[live.laugh.love]

For the past, 3 days i keep getting this odd sharp pain in my spine. It comes randomly, and when it does it's so sharp every muscle locks during the pain attack and then unlocks after. it comes randomly but the pain only lasts for about 5 seconds at a time, but has happened about 9-13 times a day! it's frustrating and really painful. it feel's as though it comes from the middle of my back, and it starts in my spine and then spreads out across my back. the sharp pain weakens as it spreads out. But it only spread in a small circle, not all across my back.

what could it be? I'm active, have a healthy weight, and am in good health so i don't know what caused it or why it's happening.

at first i though it was how i was sitting, but i changed the way i sit and even do stretches after a long sitting.

btw i broke my toe nail about 9 months ago and its growing ingrown, could it be some side effect of that?

please some advice?

thanks