Go with your gut! I can't tell you how many times Doctors told me my neck, head, arms and shoulders can not be related. Did they ever pick up an anatomy book?

Find a highly skilled PT ASAP. A bonus would be if they are familiar with and have treated TOS. If they hand you therabands or give you strengthening exercises, run for the door. I have found myofascial work to be of great benefit, but your body may respond to another form of therapy. You also need to get any emergency vascular issues ruled out. Yours sound more positional related.

People have gotten a lot of help by propping their arms up at night with pillows. This may help some of your blood flow and numbing problems. Lifting is the one move I try to avoid as it seems to strain every muscle involved. I can move bags of groceries and things of similar weight, but a child would be tough. It's probably close to impossible to avoid lifting your children, but if you can explain to them "mommy is hurt", they may cut you a few breaks.

Meditation and relaxation techniques are helpful as well. It may be a hard to get time to yourself with twin 3 year olds, but if they nap or go to school, use this time for yourself, not to clean the house, do laundry, etc.

Even though it's been 5 years, I don't think it's ever to late to heal. Good luck!