Changes in abdominal girth can have many different causes. Although bloating is possible, you would want to get checked out by a doctor to be sure. The best type of doctor to see for this problem would be a primary care physician
such as a family doctor
or internal medicine doctor
In general abdominal bloating is due to gas that is trapped in the GI track. This happens because we swallow air when we eat and drink. Most of this gas leaves the body either through burping or through passing gas through flatus. Severe bloating associated with abdominal pain may be an intestinal obstruction. If you are having normal bowel movements, than an obstruction is unlikely. Another cause of increased abdominal girth is ascites (fluid in the abdominal cavity). This can be caused by liver issues, heart issues, or kidney issues.
I suggest that you schedule an appointment to see your primary care physician. He or she can take a more detailed history of your abdominal issues and perform a thorough physical exam. If anything is found initially, you doctor may order some abdominal imaging such as an x-ray or CT scan. If nothing is found, then you may ask your doctor if it is okay to take some over the counter simethicone. This gives some people relief.