My son had occasional hypothermia (usually around 96, but was 95 once!) 3 years ago, AFTER he was started on Thyroxine for hypothyroidism. His endocrinologist didn't believe me, because of course, Thyrox. should keep his temp. in normal range, but it didn't always. I know he was absorbing it; he had adrenal collapse one week after he started it, and had to start Hydrocortisone for low blood pressure and cortisol loss. (He had a pituitary tumor). I think his tumor may have caused hypothalamus damage, leading to his Dysautonomia, but his surgeon doesn't think so. Raising his T4 just a little bit causes tachycardia.
Now he is too warm most of the time, never hypothermic anymore.
Because of his digestive problems, I have sometimes wondered if his pyloric valve is getting "stuck" on occasion. Interestingly, my pyloric valve would not open a few days after I was born. I had to have surgery at 14 days old to fix it. That was 55 years ago! Maybe something genetic here? (We're all redheads so, recessive genes?
I have low body temp. too. All my thyroid test come back normal. One doctor said I have a problem with the T4 Converting to T3. So we tried T3 to see if it would get my body temp up. I never could and it affected my heart rates. Not good. I don't suggest trying this. They call it Wilson Syndrome. But, now if I'm really tired I have freezing spells and then they go to hot flashes, later. I'm sure is connected to the ANS.
The autonomic nervous system regulates your body temperature, so a low temperature I'm guessing could be a problem with this. My son's regular body temp is around 97. He doesn't experience the coldness though, he gets hot spells.
Coincidentally, when my son was a toddler that muscle which opens and closes to the stomach was also open. His pediatrician said it just needed to strengthen to close, but I now wonder at alot of stuff he had then were symptoms or a precurser to the dysautonomia he has now.