cccmama3000—
Just a few thoughts: If you are underweight you could be hyperthyroid, which could be exacerbated with the abx. There's a little triangle area right at the base of the throat, which as LP said is where your thyroid is located—is that where you're feeling the constriction? Perhaps it's agitated and a little swollen—just a small change in size could feel huge.
Check out
stopthethyroidmadness.com website for more info—I'm hypothyroid so don't have much more to offer you, unfortunately.
Also, if you have Bart, one of its symptoms is stirring up trouble in your GI. One real cheap and easy way to test to see if it is a GERD issue or bile issue is to take some HCL (you can likely buy it at most drugstores) and see if you feel any relief. I now realize I have had "bell's palsy of the gut" due to Bart and parts of my digestive tract simply stopped functioning, hence the bell's palsy. And whenever I ate my body was trying to digest solid foods, since I had no acids in my stomach. And of course, my docs were prescribing ant-acids.
I then found an ND who specialized in GI and hormonal issues who realized what was going on (although we still didn't know why—didn't get dx w/ lyme & co. until 4 yrs and $22k later…) and had me start with 1 HCL capsule before each meal, increased it to 2 the next day, and kept increasing the dose until I started really feeling/tasting too much acid, then I stepped it back down. I got all the way up to 9 capsules per meal, which shows how much acid I had to reintroduce to jump start the stomach (or pancreas) again. Three wks later I was off the HCL and eating solid food again.
BTW, I'm following your progress closely, as I am getting my port installed next week… So I really hope you find some relief—you have enough going on!
-p