For some immediate pain relief, ice that spot on your lower back. For getting to the core of the problem, see a good chiropractor. A good adjustment at the chiro’s office can make a lot of difference.
References :
a satisfied chiro patient for 9 years

A pinched nerve is caused by a disk pressing on your siactic nerves, you might have spasms, lifting something heavy. Excercise is good, but not to much. If you dont take care of it, you will continue to have pain , and taking pain meds. I was in a car accident 1 year ago then all of a sudden lower pain in the lumbar area. The spine wasnt straight, so going to a chiropractor is good, physical therapy, or home or gym excercise is good to get the pressure off. Thats how i got my pressure off, because you dont want surgery in the future. YOu also can get shots in the back, but they were off. Take it easy avoid any major lifting, pulling, bending. Have you had an xray ? if not you might need one or an MRI. Try buying a chiropractor pillow that you can use for driving, try sitting up straight to stretch the muscles. THe pillow if you have that type of job you can use it at work. YOu also need good pillows at home.
References :

i have sciatica and the only way I can get some relieve when its acting out is to get off my feet and relax on my recliner with ice and heat therapy. First ice 30 minutes, heat 30 minutes etc. It helps a lot.

But when things get bad too often I know its time to get an appointment with my chiro / massage dude.

I’m assuming you already know for sure its sciatica because a doctor told you… if not have it check it out.
References :

apply a heat pillow
to lessen the pain ^^
References :