Hi I Am 28 Years Old I'm Suffering From A

Hi I am 28 years old I'm suffering from a weird feeling in my stomach usually above my belly button and left side of my stomach sumtimes I get the odd sore bit and I've got to ly down as it makes me feel sick but most of the time it feels like there's sumthing inside my stomach kind of hard to discribe been constipated to in the past and been straining sumtimes when I go to toilet could this be a prob been to doc and they gave me tablets for trapped gas but not seem to b working it's really working me x everyday I have thins been going on since about 6 weeks. Also the weird feeling goes thro to my bk to causing a sharp pain in centre of my back