Seats might be contributing to my musculoskeletal condition...

So my car was in the shop for 3 weeks, and during that time, I drove a family member's Honda Accord. Curiously, the neck and upper back pain I experience daily with fibro lessened significantly. When I began the 3-hour drive home, the pain returned almost immediately and by the time I got back, I felt like someone had plunged a knife through my neck. This made me think--I'm sititng on an 18-year-old, heavily-driven seat that probably has absolutely NO padding left. And let's not forget the notoriously uncomfortable forward-tilting headrests.

I'm giving serious consideration to having someone re-pad and re-upholster the seat. Before I go that route, any recommendations or suggestions? Any quality (not crap) full-seat support inserts out there? (Most of what I see on Amazon or Advanced Auto or Wal-Mart are lumbar cushions only).

Advice appreciated.