I took aleve (naproxen) and have now been suffering from stomach pain for hours, how can i relieve it, when should i worry ? has happened before with ibuprofen

Peptic ulcer disease: Peptic ulcer disease (PUD) encompasses heartburn, acid reflux, and even ulcers. PUD is a known side effect or complication of NSAIDs. Calcium carbonate might help mild cases, as can H2 blockers & even PPI. Try OTC 1st. Failing that, go see your Family Doc. If you feel weak (b/c anemia b/c bled out) go to ER for immediate eval. In meantime, avoid naproxen & ibuprofen.