Hi Jess,
Have you ever tried TENS? (Transcutaneous electrical nerve stimulation). Some PT's use it as an adjunct to very tight or spasmed muscles. My insurance bought me a TENS unit several years prior to my surgery when I was going to PT, and it can definitely help with really tight muscles. Mine was a small portable unit, a little bigger than a cell phone, that clipped to my belt and had two sets of electrodes to work on two areas at once. It's the only thing I can think of that you haven't mentioned.
Take care, I am so glad that baby Sparky is healing!
Gayle, age 50
Oct 2010 fusion T8-sacrum w/ pelvic fixation
Feb 2012 lumbar revision for broken rods @ L2-3-4
Sept 2015 major lumbar A/P revision for broken rods @ L5-S1
mom of Leah, 15 y/o, Diagnosed '08 with 26* T JIS (age 6)
2010 VBS Dr Luhmann Shriners St Louis
2017 curves stable/skeletely mature
also mom of Torrey, 12 y/o son, 16* T, stable