Burning pain in lower abdomen above pelvis but below stomach, caused by excess gas?

Possibly: Irritable bowel syndrome can cause these symptoms, but so can ordinary gas. Sometimes we can have sensitivities to foods that we don't process well. Celiac disease is a sensitivity to gluten - a protein present in wheat that can cause significant symptoms. If these symptoms persist you should definitely be evaluated since there can be serious consequences to some of these problems.

There isn't enough: info to tell you the cause of your pain. Note that you have listed constipation as condition. If you are experiencing that currently - it might be the cause of your abdominal pain.