Shoulder pain/discomfort

Probably the age old question: About 3 months ago I began to add more and more freestyle (crawl) to my swimming workouts in preparation for an open water event. Sounds stupid, but it is not my favorite stroke, I am more centered and comfortable with breaststroke. I am sure because of poor technique I may have re-injured my left shoulder, same shoulder that used to give me problems in high school and college swimming years and years ago. I have not been swimming for close to two months, been on some steroids and NSAID's as well. Still have a little discomfort with the full range of motion, but thinking that I could get back into the water for some workouts. I am in my 50's, and because of an Achilles injury I rely on swimming for my exercise (and sanity). People I work with REALLY want me to get back into the pool as well.... something about being grumpy :-) Suggestions for returning to my routine? Before I did whatever I did I was a 6-10K a day swimmer, two days a week and 5-6K, three days a week. Thoughts?