Hi, thanks for using healthcare magic

Most doctors are taught that increase in weight is due to the three f's- fluid, fat or faeces, with fluid and fat being the most common culprits.
You stated that you are an insulin dependent diabetic with an underactive thyroid. Both of these (the use of insulin and hypothyroidism) are associated with increase in weight. Insulin has many roles in the body, one of its functions is to decrease the metabolism or breakdown of fat and use of insulin or increase stimulation of insulin secretion by use of a high carbohydrate diet, result in storage of fat.
This is one of the theories behind low carbohydrate diets- reduce insulin secretion (carbohydrates are the main stimulant for insulin secretion or the need for insulin) and increase the breakdown of fat leading to weight loss.
Because the thyroid hormone affects the metabolism of the body , low levels can cause a decrease in metabolism and weight gain, this is the reason persons with hyperactive thyroids complain of excess weight loss.
There are other hormone that can potentially result in weight gain if there levels are not normal, they are : cortisol- increase levels of this hormone can result in weight gain,levels are checked by an early morning blood test,(2) excess levels of growth hormone in adults cause a condition called acromegaly which is associated with increase in tissue

In terms of fluid accumulation, any condition affecting the heart, kidney or liver can potentially result in accumulation of fluid and increasing weight. In addition in persons with low blood protein levels- fluid accumulation would also occur. The presence of any of these conditions is confirmed with blood tests (for the protein level,kidney, liver) and an ECG/echo for the heart.

Increase in weight would contribute to the back pain because our frames are meant to carry only a certain amount of weight and increase in weight increases the pressure on our weight bearing joints ( the hips ,knees , ankles and back).Lower back pain can also be caused by muscle strain or spasm, arthritis- usually felt witha stiffness that may occur on waking, prolapsed disc, multiple myeloma.Diagnosis requires history (to assess for any history of injury, neurological symptoms, nature of the pain), examination and ,depending on the result of both of these, appropiate investigations such as blood tests or xrays.
Abdominal can be caused by inflammation,obstruction or inadequate supply to any organ.
Abdominal pain can have a number of different causes which are determined by history including info on : the site of the pain, the nature of it( how it feels, is it constant or intermittent,its duration), if it radiates or goes to another site, what provokes the pain (certain movements or positions, certain foods) and the relieving factors, any associated symptoms like urinary discomfort, appetite changes, changes in bowel movements,fever, vomting or nausea, urgency or frequency to urinate, vaginal discharge, painful intimacy etc
Surgical causes of pain are usually associated with fever, in some cases decrease in appetite, history of previous abdominal surgery.
Exact diagnosis may require visiting your doctor for an abdominal examination , so he or she can determine if there is any tenderness on palpation, check the bowel sounds which are abnormal in obstruction, feel for any concerning masses.

I hope this helps ,feel free to ask any other questions

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