I Went To Hospital Last Night Cause My Back Right

i went to hospital last night cause my back right below my chest was hurting but it comes and gos but when it comes it comes on like a charly horse really bad one i feel like some thing moving but it sooo pain full it just comes out of no where he said i could go back to work how iam going to do that not sure but after i get the pain it stays for a wile then gos a way but i feel the after pain just set there i cant even move when it happens they said it was a strained muscle tissue or twist or tear ? iam in so much pain dont know what to do