I have the same problem sometimes, its most likely
gas pain. When I need to relieve
gas pain in my chest and upper back I drink about 2-3oz of lemon juice in a glass of water and take a few gas x. It helps me a lot. Try not to drink carbonated beverages after 6pm, and drink the lemon water after dinner and before bed to help relieve the pain all night long, It works wonders for me.