How do I know if Gluten Intolerance is causing my pain?

A year ago I was having terrible bloating, gas, my feet were throbbing and burning, I had difficulty with bowel movements at times and awful smelling bowel movements. I also experienced a number of nights where my entire body felt inflammed and hurt all over! As a result, I did not sleep those nights. After a CT Scan that said things were normal, I was sent to a Gastroentrologist. He told me after a Colonscopy and Endoscopy they found signs of Celiac Sprue, he instructed me to go a Gluten-Free diet because but they could not see that definitely I had Celiac's disease. I went on the Gluten Free diet and lost 30-lbs. in a short 10-week span. However, I feel part of the weight loss was due to my greatly reducing my intake of soda pop. I had been drinking 32-40ozs. daily of a 3/4-diet, 1/4-regular soda combo. I also think the stress of worrying that the Celiac was going to lead to cancer also led to my weigth loss from stress. Eventhough I lost the weight, I went back to the Doctor because I was still experiencing sharp burning pain(s) in the middle of my back, between my shoulder blades, more on the left side under the shoulder blade and I still had diarrehha and frequent awful smelling gas and bm's. In May 2010, the Gastro doc had me take an extensive gene test and he said the results were that I did not have Celiac and that I could resume eating normally. Well, almost a year later...sadly I have gained about 25lbs. back, I am drinking about 24ozs. of the diet/regular pop combo again. In addition, I get the severe pain in my back and burning throbbing in my feet, sometimes all day. I have not maintained the Gluten-Free diet but I have tried to stay away from processed food, breads, wheat prodcuts, etc. So, how do I figured out what's going on with me!? After the gene test in May, my dosctors began prescribing Omeprazole 20mg a day for what they felt was heartburn or GERD (Acid reflux). The final straw for me happened last Thursday (3/23/11), after a great Spring vacation with my family I was back at work a few days and a spaghetti luncheon. Within about 20-minutes after eating the meal, my stomach became a washing machine of pain and my hands, hips and feet became inflammed. The next evening, Friday, I had such pain in my back while coaching my son's indoor soccer team that I nearly passed out! I woke up for 2-3 days with tremendous joint and back pain. Now, I realize I am 44-years old and overweight but I was doing Great the week before. Please help!! GOD'S PEACE, Sleepless89