What Causes Persistent Pain In Ruptured Ulcer Along With Constipation?

My son is currently hospitalized due to continuing pain from a ruptured ulcer that perforated the stomach and intestine. He underwent 2 surgeries around thanksgiving , he was released after 12 days. He subsequently developed pain, he was admitted for tests and he hasn't had a bowel movement for 8 days, even after being given severla medications to make his bowels move. Could the intestine be blocked from the surgeries and what else can be done?