Hi,i'm having a bad feeling in my stomach when i'm drinking the coffee,maybe there is a lactose in the coffee?

No lactose in coffee: There isn't any lactose in coffee unless you add milk or creamers. Coffee itself can often contribute to stomach upset, acid reflux or aggravate stomach ulcers. If you continue to have stomach problems even when avoiding coffee this should be evaluated.

Reflux: Sounds like gastroesophageal irritation probably via reflux. May want to consider giving up caffeine for a few weeks and see ho that goes.