To answer your first question on what you're first visit might be like,.....well we won't know for sure, but he will probably put you through some sort of movement test, and ask you several questions while doing so.
The PT can be uncomfortable, as they will want to push your muscles to the limit and give them a good stretch. It is very common to see these guys 2 to 3 times a week at first. Then, when you have been given the proper instructions for stretching to do at home, they may see you less often, as long as you are doing your homework assignments they give you.
If you are not seeing much improvement after several weeks of PT, then an Epidural may be suggested to you. A person can see quite a bit of improvement from this, but then again it will not help everyone.
Are you taking ibuprofen for inflammation? Many Dr's suggest this as well, along with the PT. Is the back specialist you are seeing a surgeon?