hi, firstly i would recommend avoiding carrying heavy bags with your affected arm as the weight is pulling your arm further out of position therefore stretching the already strained muscles which will be helping to keep the joint in place.. it would be highly beneficial to have a scan on it if possible, this way no-ones personal diagnosis and prescription can make the issue more complicated..
the feeling of your lung entrapment is most likely to be coming from the lung meridian which has it's 1st and 2nd acupoints which are approx 1 inch (respectively below the protruding bend of your collar bone, gentle manipulation of these points would release the blockage and most likely relieve this sensation.. you could easily find these points yourself and gently massage them, they will probably be painful to touch but this would subside through you "working" them..
i believe this would help the inflammation as would tuina massage help to relieve the whole neck/shoulder region as the muscle spasms will begin to cause tension to spread further.
i agree with Milan in saying that cupping would be a good idea also as it will release stagnant blood from the area and introduce new blood and aid the healing process of the damaged tissue.. i would also recommend gentle tuina therapy to the area to stimulate the tissue/acupoints in the area..
a good Chinese acupuncturist would also be able to help with pain relief remotely..
an experienced physio with skills in taping would also be worth finding as this would restrict the movements causing you difficulty and reduce muscle stretching without looking at a strap..
suppliments in mind i would advise "green lipped mussel extract" is it combats arthritic conditions and aids damaged tissue.. this can be taken internally by capsual and spread on the area in a cream such as pernaton, tiger balm and red flower oil or woodlock are also excellent natural oils which would help with keeping the area supple and aid healing..
good luck, colin http://www.tuinainedinburgh.com