9 months is a long time for this excruciating pain, doesn't sound physiological. It is radiating to thigh seems like lower backache but not due to muscles either. There can be two conditions it can be increase either forward bending and backward bending, do notice it. As you mentioned walking and sleeping is difficult and radiating to thigh. First thing i'd suggest to you to take a complete rest, don't sit down on floor, don't bend forward and backward too much. Don't go for PT without being diagnosed first. Range of motion can be done but not advanced one.
Next Steps
Go visit to nearby doctor or consult on practo practitioner. First investigations need to get done.
Health Tips
Don't do vigorous activities.