But look for a chiropractor first, and blockage of movement might be a sign of sprain, misaligned joints. It will not heal itself, but if after telling a doctor the movement restrictions and they tried to force it that direction you might want to change another professional as it might cause a dislocation.
If you want you to try fixing it yourself you can start by doing some stretches and see if it loosens the joint so you can ease your way back. If it hurts stop immediately, DO NOT FORCE.
For the stretches that you can do, i don't know which unless you know someone who is familiar with stretches. Know where is it locking up and try to stretch the major groups for up to 5-10 mins.
You can try this method La-Jin Therapy and Pai-Da Therapy.ppt
it is a powerpoint. Stretches are from this guy E-TAO
This might help
Massage May Be Better Than Meds for Relieving Back Pain
NOTE: you need to find a really good one, someone who is trained and knows where the major ligaments and tendons are; not those kneading massage as it only eases and can't solve the problem.
IMPORTANT: If it hurts, don't force it.