Click on the large heading "Forum" at the top of your page.
Scroll down to the appropriate section you are looking for. Most of the posts here are under the shoulder heading, and you can click on "general discussion," "surgery" or "physical therapy and recovery."
You will see a link that says New Thread. Click on it and it will bring up a blank space where you can type your questions. When you are finished, hit submit and there you go!