Discomfort in the Back of my Throat

Hi, my name is Nicole and I am a 24 year old female and have been experiencing many negative health complications and am praying that someone, somewhere will be able to help guide me in the right direction to get these issues resolved.

About 4.5 years ago I gained an enormous amount of weight in a very short period of time.  From when I left for my second year of college in late August to November when I visited home for Thanksgiving I gained about 35 pounds!  My mother was frantic and had my glucose levels tested as well as my thyroid and anything else that was recommended by my primary care physician at the time.  Everything came back normal.  During this time period I felt the weight gain and was hitting the gym 3 times a day as well as trying many different diets, nothing shook off the weight.  Something my physician pointed out was that I have always had abnormal bowel movements and what I call chronic stomach aches.  I get the stomach aches about 2-3 times per week and they are VERY SERIOUS.  They begin in my upper ab area and are immediately followed by bowel movement (so immediate that I have had to pull over on the side of the road to squat to avoid going in my pants).  My stool is generally a lighter shade of brown when this happens, is soft and has a lot of mucus in it.  The pain in my stomach lasts for about 15 minutes, sometimes causes me to sweat and gradually moves down to my pelvic area.  What I experience is an internal pain and some cramping on my outer stomach.  The pain immediately goes away when I am done on the toilet.  When it is gone for a few minutes I finish in the bathroom and less than 5 minutes later I am back on the toilet.  This occurs about 2 more times until it goes away entirely.  The doctor analyzed my food intake for a period of 5 days and there was no correlation between my stomach aches and common allergy food intake.  About 2 years after that initial weight gain, I gained 20 more.  At this same time had my first experience with heart burn and it has gradually gotten worse and is something that occurs about every other day now.  I also developed this discomfort in the back of my throat like there was a piece of rice back there.  Some days it's worse than others, but has remained there for the past 2 years.  My physician prescribed me a Proton Pump Inhibitor to take daily and that has not helped one bit.  I've been tested for Celiac Disease, have even been given a Colonoscopy as well as an ultrasound on my stomach and nothing has come back abnormal.  These issues have gotten in the way of me enjoying my life and I am more than ready to get to the bottom of this, even if it means being diagnosed with something severe.  PLEASE HELP ME!  I would love to hear any suggestions for possible treatments I should look into or if anyone has a similar story, I'd love to hear it.