My Husband Is 53 Yrs Old. He Was Throwing Up

My husband is 53 yrs old. He was throwing up last night and this morning. He thinks he pulled his lower back somehow. The pain has moved to his hip, groin and thigh. He can't take anything for pain because he hasn't been able to eat a lot. He wants to know if he should go to a clinic or if he should just use heat or cold to ease the pain.