Nope. A shoulder holster cannot be concealed in 100 degree weather. I don't do shoulder holsters. I really think I had pressure on this spot while sitting leaning against my flashlight-leatherman case. I put that on the other side. I've also exchanged my 85UL for my naa black widow. My back has been getting better.
I'm carrying my 14 ounce Kel Tec 9 on my belt last couple of days. 21 rounds for the primary eases my mind.