Hello! Thank you for the query. Such symptoms ca be caused by chronic bacterial infection. It seems most probable as antibiotics were used and you have found it helpful for a while. You need to know that intestines are protected by good bacteria. This bacteria prevent bad bacteria from growing. Any antibiotic destroys good bacteria what allows bad bacteria to grow. Another possible reason of your symptoms is partial bowels obstruction due to Crohns disease. However as colonoscopy was negative, this is less probable. I suggest you to start with stool test and stool culture test. Discuss with your doctor Rifaximine treatment. Regards.