and then my back hurts like hell for the next hour

for some reason sometimes I have like these episodes of temporary paralysis where like; if I sit down wrong my back will fully straighten and then when I try to get up I have to focus all my energy on even moving my arms forward and don't even get me started on how hard leaning forward an inch is so I have to sit there for like 15 minutes trying to re-correct my posture so that I can actually move again