Brief Answer: Need some more details Detailed Answer: Hi, Thanks for your query. There are several causes of stomach pain (pain in left side) but besides saying pain in left side please also mention: 1.How long you feel this kind of pain? and how long the pain lasts? 2.Nature of pain eg dull ace, sharp or like abdominal cramp. 3 Timing of pain and its relation to food (eg in empty stomach or full stomach) what causes relieve of pain? But to generalise the causes of stomach pain mainly arises due to: :1.Indigestion 2.Constipation 3. Abdominal infection 4.Food poisoning 5.Food allergies 6.Gas 7Lactose intolerance 8.Ulcers/ Gastritis 9.Gastroesophageal reflux disease. Besides several other causes also can cause stomach pain so a thorough physical examination and routine tests are necessary to arrive to trace the cause of pain so that treatment can be directed to rectify the underlying problem. In general if you have pain due to peptic ulcer or acidity than any antacid specially Ranitidin (150 mg) twice daily will solve the problem otherwise a detail examination may be necessary to solve this problem. With best wishes from Dr Chowhan

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