My therapist taught me diaphragm breathing to relieve pain and tension. He also has me doing bridges which he says is the best back exercise. They help me a lot and if my back is aching before I get out of bed I do them while I am still in the bed. Try to get up and walk around whenever you can and try to get an aisle seat. If possible upgrade your seat, I can’t remember what they call them but the seats have more room and recline more than the standard.