Until I read you 3rd to last paragraph, I was going to suggest your 'social anxiety' was due to the multiple voices. This is a common problem. The brain wants to understand all of the sensory inputs it receives. In a healthy brain, when it hears multiple voices, it has a filter mechanism that will disregard most of the voices and only focus on those nearby.

With PCS, this filtering mechanism is often damaged. The neurological term is "gating." It has lost its ability to gate sensory inputs to the correct stream or to ignore (block) it from passing the gate.

The simplest solution is to get some foam ear plugs and where them when in a multiple voice situation. You will be surprised to find that they do not block near sound too much but do a good job of blocking the ambient and distant sounds. What they do best is improve the contrast so the near sounds come through with good volume and the ambient or distant sounds have big drops in volume.

I find the yellow cylindrical foam ear plugs work best. The bell shaped ear plugs are less effective. Twist the foam plugs up tight. Insert then deep into your ear so you can barely touch them. They will expand to fill the ear canal.

The ear plugs with strings in them are lousy. The strings transmit the sounds.

Do not feel embarrassed to wear them. A simple explanation of "I have an auditory processing disorder due to a concussion" is well received by others.

I have been using this trick for 10 years. I always have ear plugs handy.

Hope this helps.

My best to you.