having severe muscle spasms in his neck and is now hunched over barely able to walk properly. 

No, not something I would call "common" with tripawds.  Not at ali!  Now, sometimes there will be twitching at the amputation site  area and that's  "normal".  But hunched over and barely able  to walk.....nah.  We need to get this addressed and getting  him feeling better.

Did this happen AFTER the Chiropractor visit or before.  If before, did the visit make it worse or better?  Hold off on those sessions until you  can get your regular  Vet to assess your pup.  Also, maybe check into a Certified  Rehabilitation  Specialist  once he gets better.  A good one is excellent in identifying any gait issues and how to build his core strength and keepmhis joints safe. 

First thing that comes to mind is too much activity  too quickly.  It is sooooo easy for a tripawd to pull a muscle  early on during recovery and even afterwards.  The first two weeks should have been short and leashed potty breaks and then back in for rest and more resr.  No jumping, no going up and down stairs unless assisted and no jumping on couch, etc.  

Obviously check with your Vet as soon as you can, , but sounds like he definitely needs an anti-inflammatory and a pain med and lots of rest  and limited activity for now.  

For now, give him gentle  massaging  up and down his neck and spine area and try and relax his muscles.  Do3s he show any tense areas when you do this?

Sorry for all the quesrions.  We'll look for your feedback.

Hugs

Sally and Alumni Happy Hannah and Merry Myrtle and Frankie too