Filipe,

No one can diagnose you on the internet. But based on your
story, it appears that you have an injury and it might heal up.

We all develop issues as we age. Strains, and especially tendon strains take a long time to heal. Tendons are constantly being stretched, and if you damaged one or more you will be re-injuring them if you overuse them daily. That is why it is important to rest them, and only gently stretch until they heal.
Tendons have nerves in them, attached to them, to give warning when overused. So it takes some time.

I'd follow the protocol for strains, which is RICE.
http://sportsmedicine.about.com/cs/rehab/a/rice.htm

You can ask your doctor if physical therapy will help. Physical therapists know how to get you to move without further injury. They use infrared, inferential current electrial stimulation and ultrasound to speed healing.

Reading the internet can be good and bad. If it is leading you to have too much fear, and worry, then you should cut back on that. At this time you have had most of the medical support available. If in 6months you are not better, then I would be concerned. But if you have a slowly improving state, then that is very hopeful. You have already had some improvements. So just stay conservative and see what happens.