What Causes Weight Gain Along With Stomach Bloating?

Hi yes I have had severe weight gain like 30pds in the last year and a half,joint aches,severe bloated stomach and lower back pain, had sonogram and gallbladder is adequatelyv distended and harbors a small hyperechoic focus along anterior wall that does not move,which represents a polyp. So is that what the weight gain is from and the severe bloating was just wondering I am under a doctors care I just received my results today