What Causes Stammering During Speech?

hi doctors, im bassam, i just want to know about 2 serious problems i have.. 1st is that i always had stammering in speech since i was 8 (im 20 years old now) and its getting worse. it depends on who im talking to and how comfortable im with, thats what i know about it, is there anything that can help me, im desperate, 2nd thing, i have excess belly fat, and this is my holiday so i started working out to get fit, i started going to the gym 5 days a week and so on, doing all types of exercises including crunches, etc.. the thing is, my belly fat is less now and i feel more power and strength but when i sleep on the sides, my lower stomach still bulges out too much! any advices? thanks