Which drug is best for stomach ache?

Stomach ache: It depends on what caused the pain. If it is gastritis or ulcer type pain, then Zantac, (ranitidine) Prilosec, Prevacid may be used. If it is referred pain from, say, gallbladder, pain killers may be appropriate. Gas pain may respond to heat and a gas reliever. Sometimes heart issues present with stomach discomfort and that requires totally different approach, so really you need to figure out what the cause is