Ok, I just wanted to check back in with an update. I tried the stretches from the video RampantBadger linked and it was nothing short of a miracle. Just a couple 30 sec holds and I was able to bench pain free for the first time in years
I had been doing the second stretch, with my elbow in line or slightly below my shoulder, fairly regularly when I felt tight, but it never helped much. I had never heard of, or thought of, doing the first stretch, with my elbow higher than my shoulder, but I knew something was different as soon as I tried it. I was so tight, that at first I couldn't get my arm past in-line with my body. Once I gained some ROM, I tried benching and had full ROM and no pain.
Next is to keep up with the stretch to make it more permanent and to build some stability in the new ROM, so I've been adding the exercises in the video FlatsFarmer linked. As I pressed, my pec wanted to pull my shoulder forward (not rolling forward like it used to, but just out of retraction) and I really had to concentrate on keeping it back. The good news is, as long as I thought about it, I was able to keep my shoulders back, so I just need to train it.
I tried getting a video, but I was training at a commercial gym the last couple days and people kept walking between the camera and bench, so I couldn't get anything good. I'm at my normal gym for the next week, so I'll be able to get one. As I'm now more concerned about my over all technique and I wouldn't mind some advice on my squat and deadlift as well, I'll probably get video of all three and throw it up in it's own thread.
Thanks again for all the help! I really appreciate it.