Doc wants me to have spinal injection for sciatica/herniated disc.is this just about $, why won't he try other options? i don't want injection.

What other options?: What other options are those? Injection is probably the most likely to be beneficial and is infinitely less expensive than surgery.

Physical Therapy: An epidural or a facet injection is a very reasonable option to treat herniated disc causing pain. Sometime the pain may be self limited and can be treated with nonsteroidal medications and physical therapy which is the best options. If the pain makes you unable to participate in pt than an epidural injections may be the thing you need to get you over the hump.

Core Exercises: Typically core strengthening exercises are the best to help relieve pressure and forces in the spine. I would try and google some or look them up on youtube to see descriptions. If you can do them yourself, wonderful otherwise ask your doctor to get a referral to a good physical therapist for further assistance. If these are not helpful then consider the injections as possible options .