Suggest Treatment For Severe Cramps And Pain In Body

My boyfriend started experiencing severe cramping all over his body and gets excruciating pain. He has started a new roofing job where he uses muscles that he hasn't used in while, so we think that is the problem, What can we do to alleviate the pain? He currently is taking Ibubpofren, but the pain is severe, he has no appetite either, Thank you.