Hey SKZ....
I can emphatize what you are going through as I just went through m 3rd cervical fusion (they went in from the front AND the back of the neck) because of 2 previous failed fusions...
The first surgery they took bone from my hip and even then, they said that my right hip (not the surgery one) pushes out much more than the other, and like you, one shoulder/side is higher than the other...I also had to have a neuroma (benign tumor) in my left foor back in 2004....
All of these things have made me very "cockeyed" and contributed to more and more muscle spasms in my lower back, right side, upper back, right side and shoulders that are just terrible and weren't changed with the surgeries for the better....
So, the suggestions that I have to live with them....(yeah...live with it

)since I work with my PM and know that after the surgeries and such that I will have pain for the rest of my life but do everything I can to live the happiest and pain "less" days....
I take Robaxin, which to me, is a wonderful muscle relaxer and better than anything that I have ever taken in that realm....All the others like Flexeril, etc. made me so tired I couldn't see straight....I take 750mg...(sounds like a lot but that is actually the beginning dose with that type med)...and it helps a lot and doesn't make me sleepy...I am also on other meds like Oxy and Percocet when needed but they don't specifically work for the muscle spasms....I also take when needed, since I am now allowed after the 3 month mark from surgery....to take Motrin IB which actually does a really good job as well for muscle pains....
I also do, pay out of pocket, for massages.....The type that actually hurt a lot but really keep those spasms at bay...the deep tissue ones....Of course my friends are like..."ohhhh...i would LOVE to get massages"....and I'm like, "It's not what you think at a spa for me....the only reason is to work out those terrible spasms and dig in there and release them"....If they only knew what it was like for us!!!
Anyway, I also do yoga, lots of stretching techniques...Physical therapy, and yes, exercise a minimum of 3 times a week strengthening the muscles in my back, neck, and shoulders and ESPECIALLY my core....my stomach....This helps tremendously with the spasms as the stronger your core is, the better posture you have and less pain for my neck/back....I also recommend making sure that you aren't carrying a lot of extra weight in the stomach area as well since that puts so much more pressure on our backs/hips, and necks....
Hope that some of these suggestions help....Unfortunately....there might be some pains and things that cannot be fixed with surgery or medicine totally and we have to live with

I am sorry to hear that you still have pain....hope you don't have to join me as an "old lady who is cockeyed"""LOL....Ok...I"m only 38 but yes....FEEL older sometimes because my body doesn't work the way I want all the time.....But hope that you can take meaures with a multi-faceted approach with exercise, yoga, stretces, massage, ibuprofen, and possibly muscle relaxers to help with the pain....
Glad to hear you are healing well from your surgery....I've been following yours and other posts and have been praying....
Blessings,
Ingrid