Hi. Thanks for your query. Noted the history stomach pain and sometimes diarrhea feeling but actually not happening, wants to know whether due to stopping of smoking 2 months ago or diabetes or lactose intolerance. Lactose intolerance is usually a problem of small children and not the adults, hence can be ruled out and can also be tested by stool tests asking to see for lactose intolerance. The pain, feeling of diarrhea but actually nothing means that you may be suffering from the following: - IBS is irritable bowel syndrome. - Colitis of any form. This can be confirmed by the following: - Tests of stool, blood and urine. - Ultrasonography and CT scan of the abdomen if required. - Colonoscopy. If all the investigations are normal, this is IBS and get treated accordingly. In such a case it is important to keep the the stress and/or anxiety well under control. Quitting smoking has a direct relation with the bowel habits and hence may be one of the causes and secondly the stress and anxiety might have risen up. This does not mean that you have to start smoking again but to take proper medication under the guidance and prescription of your Doctors.