Due to my shoulder problem I now have to stretch as much as I hate it. But I’ve read conflicting information on how much tension one should apply and also about duration of the stretch. For arguments sake we will be using static stretching. Any suggestions? Thanks. Ciao. 
A point of mild discomfort for at least 10-15 seconds should do the trick. You might need to “ease” your way into that final position, though.
Eric is right on the money with that one. He sent me a great article on rehab for my shoulder (also thank to Nate). It turn out I have a frozen shoulder. I moved too hard and too fast in trying to regain strength I lost while on a traveling assignment.
I would also recommend that you use heat before stretching (heat packs and ultra-sound, if you have them). Also keep track of your range of movement, see if you can slowly improve it. With luck I will get my full range back in about two months.
Best of Luck.