Damaged stomach lining can be healed - but you will first need to reduce/eliminate the amount of acid that is being produced. A good start is to take a daily dose of Zantac - this will reduce the amount of acid, allowing the stomach lining to rest and ideally repair itself. You should definitely speak to your doctor, however - he/she may feel a prescription medication, such as Nexium, would be a better alternative.
You should avoid eating before bed to make sure your stomach is empty prior to laying in a vertical position - when there is food in your stomach and you are lying down, the food can cause excess acid production.
Your symptoms may be a sign of an ulcer, yes. However, it is more likely that you are suffering from a condition called GERD, or excess acid production. Again - speak to your doctor about your symptoms, begin a daily Zantac regimine, and avoid (for now) all of the foods that cause you problems. In a few months, if your stomach is feeling better, you can slowly start adding the foods back into your diet.
If you have additional questions, feel free to ask!