Pain in the shoulders can sometimes be from the shoulder, the shoulder blade or form problems in the neck.
If your girlfriend is still having a problem, the doctor should refer her for xrays or other imaging and refer her to a physiotherapist. A physiotherapist would give her information with regard to the type of exercises she should do.
In the meantime you can purchase anti inflammatory gels that you can massage into the shoulder and shoulder blade. The message may also help if there are any tight muscle knots in that area. Any tendon and muscle tears do take a few weeks to heal. She may find a heat or ice pack helpful.
In addition to CP3kids great advice, also see if there is some sort of repetitive motion she is doing which may aggravate or feed into the problem. For example, some purses have contributed to developing bursitis...which could have been avoided with a different style if purse or letting it hang over the shoulder differently.
I wish I could tell you an easier solution than to visit the MD and get an MRI done of her shoulder, but that will truly get to the bottom of her problem. Check with your insurance first to see if they cover the MRI and if so, demand one from your physician. They are there to work for you, and if you're not satisfied with what they tell you or do for you, find another letting the original one know he's been fired. It may be something as simple as a strain to the rotator cuff, but it also may be a tear. In the interim, if she is not taking any over the counter anti-inflammtory medicine such as generic Alleve (Ibuprofen) please have her do so and see if that helps her out. Also, Icing the area several times per day may help after the initial injury, but this long into it, she probably needs moist heat more. Please let us know how you make out and Good luck to her!