Lots of condition can cause low back pain
. Most commonamong them is mechanical pain
which is due to muscle spasm
due to inappropriate sitting or prong standing. As you told you also have sciatica
which can be due to nerve entrapment which can be diagnosed by mri spine. Another condition is arthritis
of sacroiliac joint. All these condition first recommendation is appropriate physiotherapy
. In sacroilitis drug is also required. It is better to take rheumatologist
consultation before taking any medicine.