I (still but going away) have/had problems with shoulders. The problems have drastically reduced over the last 2 months due to IMO a number of factors.
1. (the biggest) I'm getting used to it.
2. I have my saddle angle bang on so there's minimal pressure on my wrists/hands which in turns pressures my shoulders less. (this also sorted out my hands going numb)
3. My core strength is slowly building up enabling me to hold myself better and support my weight.
The only saddle I get on with is a charge spoon, although its a little wide so im about to try the knife. Everything else is just wrong wrong wrong!
Ps. I had a bike fit and I've changed almost everything since then. Bike fits are ok, but they assume too much IMO. The only way to get it right is trial and error, but be careful of change amounts and frequency.