If Grace has Gastroparesis, it can be treated. There aren't very many meds, but there are some. Dietary changes can also help.
However, you'd probably have to do the gastric emptying test before her GI will give her meds. Typically with Gastroparesis, you'd have nausea and fullness after meals. Abdominal discomfort or pain. Possibly vomiting or weight loss, depending on how severe it is.
There are a number of different medications that can be used for amplified pain besides muscles relaxants. Antidepressants like Elavil and Cymbalta are sometimes used. Anticonvulsants like Gabapentin and Lyrica can also help.
M is currently on Lyrica. We can't really tell if it helps though because her AS is flaring.
I do think the pain program is worth exploring (even if you have to do it in the summer). It did help M - she is more active and stronger, she is eating better and is barely using her tube and she is weaning of pain meds very slowly. She sleeps better, though she does sometimes have bad nights because of pain. She can do a LOT more during the day and is just more functional.
However, in her case we still haven't gotten the AS under control so that is just making everything worse. We are going to do steroid shots into her SI joints because they're her worst joints right now.
It's tough with both JIA and amplified pain. I hope your pain management doctor has ideas.