For what possible reasons have i always got a bloated stomach?

Yes, but...: When you say bloating are you relating expansion of your abdominal circumference to feelings of distension, fluid retention, constipation, overeating, or do you feel pregnant? Hard to answer your question without further information and clarity. Over what period of time have you noted the swelling--minutes or months, and what are your underlying medical problems (alcohol, liver &/or gut disease).