Find a professional (DC, MD/DO, PT, ATC) in your area who knows lifting and how to assess movement dysfunction. One or two visits to get an assessment, explanation, diagnosis (if one is necessary) and treatment. Based on how bad your shoulders are, you may need a bit more. Most good practitioners will want to help you get well and manage it on your own.
You have already admitted you have pain and problems, so let me ask you this: If you've read these articles and were able to come up with the fix on your own by now then why haven't you? See someone who does this for a living, get some in person guidance and get back on your way.