Hi, welcome! TOS often puts people through a parade of doctors before they get a diagnosis and generally another parade follows in search of treatments....

I've started taking a medicine called Memantine for my TOS pain/chronic pain, but a couple other people said that it really helped them with depression.

With TOS, the scalene muscles are often tight, or in the case of a car accident, they could be tight along with scar tissue.

Have you tried doing any physical therapy exercises for TOS? A lot of them can be found online. To improve your posture, consider wall pushups to strengthen the rhomboids. There are several stretches for the scalenes and pec minor that may help as well.

Also, having an ergonomic work station should help at work - I had a split key keyboard and rollerball mouse.