I had an injection of steroids down near my butt bone, but i was told i had arthritis in my l4 and l5,why down there? in pain and a bad headache

Epidural Steroid Inj: or injection into the facet joints can be used to confirm an arthritis diagnosis or treat the pain from spinal osteoarthritis. After an Epidural Steroid Injection, you may experience a headache. This occurs in less than 1% and this is temporary and will wear off in 24-48 h.. Drink water, take pain medication and Metamucil for constipation. Take care.

Not sure: You may have arthritis at L4-5 that is causing a pinched nerve. The injection may have been around the sciatic nerve (I'm not sure). I would recommend weight loss if you are overweight and seeing a chiropractor. If the symptoms worsen you may need a consult with a spine specialist.