I had some bad problems with my shoulder - I couldn't lift for a year. I turned 45 and was completely frustrated. Tried all kinds of things - chiropractic, acupuncture, anti-inflammatory medicine, rest, ice, heat, nothing worked until...
1st, I went to Costa Rica on one of my business trips and asked a friend there. They got me an aerosol spray called Voltaren, a non-steroid topical spray. I had immediate improvement in shoulder. Just follow the directions - pretty simple.
2nd, I read a book about recovering from joint injury and took this advice: Use less weight and do negatives. For instance, on bench press, go up on a two count and down on a 4 count - no explosive motion and aim for 10 reps. Less stress on your joints that way.
I can't say I'm as strong as I was before the shoulder problem but have been lifting pain free for a year now so I'm pretty happy about that.
By the way, book also recommends stretching exercises which I am not as diligent about and eating a lot of vegetables with anti-oxidants such as brocolli, cauliflower, green beans, etc. which I try and follow pretty closely.
Good luck, Derek, hope it gets better for ya.