What Causes Abdominal And Lower Back Pain With Frequent Bowel Movements?

Hi. My boyfriend has been in pain for the past 4 days and we cannot seem to figure out what is wrong. He has very frequent bowel movements and an extremely upset stomach. Everything he eats seems to upset his stomach. He also complains of being sore and his lower back is hurting. He also said that he often feels a sharp pain like being stabbed in his stomach area. I don t think its the flu because this has been going on for more than 3 days now. He has been in so much pain he cannot seem to leave the house to go to work.