Constant stomach pain and burning sensation. what should i try for it?

Possible PUD?: There are a lot of possibilities, but your description of burning stomach pain raises the probability of gastritis & ulcers. Stop any non-prescribed nsaid's (aspiriin, advil, aleve, (naproxen) motrin, etc.) & start an otc acid reducer (like Prilosec otc, Prevacid 24hr). Seek emergency care if lightheaded, worsening symptoms, vomiting coffee ground material or passing black stool or blood. Call your doctor.

Many options, but ..: Gastritis/esophagitis, peptic ulcer diseases are some possoibilities and you can try: pepcid, tums, zantac, (ranitidine) zegerid, priolosec, or Prevacid etc...If your symptoms are new and go away in a few days with or without treatment, i would not worry much. However, if symptoms have been bothering for long time now, you still can use the above meds, but should consult doc for an evaluation. Good luck.