I believe you may have suffered a muscle strain
, maybe even a partial tear. What the muscle and shoulder desperately needs now is absolute rest in some sort of "sling"!
But, it seems you really want to "hit the road" again; which is rather unfortunate. May I suggest you give your body time to heal. There can be another try out.
You may also wish to consider the advice of an Orthopedic Surgeon or Clinical Physiotherapist.