Well, without a clinical evaluation it would be difficult to determine the cause of your pain. Possibilities that may need to be considered include gastritis, peptic ulcer, chest wall inflammation etc. With the symptoms the possibility of cancer cannot be ruled out though there is no reason to specifically suspect it. I would suggest getting this evaluated by a primary care physician initially and depending on the cause diagnosed/ suspected, it can be managed accordingly or specialist care may be sought. Meanwhile you could try some OTC antacids and see if these seem to help.
Hope this helps.