Sternocleidomastoid Trouble

Can a Sternocleidomastoid issue cause throat tension, vision disturbances, and spasms inside the ear?
I have a very slow healing injury to my collarbone that has greatly effected my sternocleidomastoid.
It is a source of constant tension and horrific spasms.
I have a feeling that the sensations I’ve mentioned are related, but want to make sure that there isn’t something more typical of these symptoms I should be asking the doctors to look into.
I understand that this is a very difficult muscle to heal and often takes awhile, but are there any tips you can offer that help in the healing process of this area?
What is the best way to loosen tension around the collarbone?
I am being treated by a chiropractor who tells me to stretch it often, but the therapies he has to offer cannot be applied to this area, so he can’t be of much help.
My massage therapist can only do so much. Any advise? Thank you.