Abdominal pain

Hello, for the past 2 weeks, my husband has been complaining of lower right abdominal pain. Between the crease in his right leg no higher than his belly button.
It seems to act up more at night. Sharp pinching pain. Localized in the one area. No nausea, though he has had two occurrences of diarrhea and feels bloated at times. No problems urinating or bowel movements except for the two times listed above. No loss in appetite or sexual functions. He does complain it hurts when he coughs. No lower back pain or any movement in the pain except the one area. Does not hurt when pushed around or on area of pain.

Two weeks ago he went to the doctor for a sinus infection and he was prescribed Levequin. He took the meds for 7 or 10 days. Whatever the doctor said to do. He finished the prescrption. He is a buisness owner and his job sometimes demands early hours and late nights. Long periods of standing. Stressful do to his hard work ethics.
He does not have a consistant diet ex. breakfast, lunch, dinner. He eats in the morning if its available or within time. Lunch is usually snacks or quick. Dinner is the only full meal. He drinks A LOT of milk vs. water. I am very careful with my diet so we only eat lean proteins, veggies, or whole grains for dinner. No high fat anything.
I hope this helps a little. Any advice would be great! Thanks for your help!
Zoe