Looks like you have low back muscle spasm which often disturbs you in sleep and while sitting on cushioned seats . Start taking aceclofenac
+ chloxoxazone tab two times a day night dose should be taken 1.hr before sleep best along with food to avoid gastric upset.
Please note if you s are sleeping in a soft mattress change to hard one avoid pillows for 5 days . Also sit and rest your back against not cushioned seats while working. Back support is must .
There are some stretch exercise for back spasm do it every morning.