I have it, but the source is I have bulged disc in my back. I used to feel pain in my butt, hip and thigh. Sometimes I felt tingling in my foot and toes. Back specialist said that I don't need surgery. I currently am pain free. Depends on exercise you perform may not good for your sciatica. My PT said if exercise makes it worse, stop it immediately. He also said some types of yoga can make it worse. There are most safe exercises like hip thrusts. Luckily, I can do squat, but I am not allowed to do lunges anymore. I had to change furniture and mattresses. Yeah, it cost money, but it works for me. No more pain and stiff.
You have to change the way you sit and sleep. If your mattress is plush, get rid of it. Go for firm mattress. Get MRI for your back and hip. If a doctor says no, go to another doctor until you get MRI. Try IKEA poang chair because it has wood supports. You have to experiment with furniture works for your body. My large couch has wood supports. My bed frames has wood slat supports. I can't sit on computer desk seats anymore. I sit on hard chairs with back support.