Lower back pain radiating to the legs sounds like ? sciatica which can be treated by an orthopedic surgeon.
Uncontrollable urination could be between
diabetes or to a simple urinary tract infection (UTI) or even an uro/gynecological problem.
May I suggest you to consult a general physician who may treat both the conditions assuming the commonest ones which may need some basic tests and depending on the test results he/she will rightly choose the treatment or refer if needed
Next Steps
Please let us know the duration and other symptoms. See a nearby doctor incase of fever, decreased blood pressure etc.
Health Tips
Avoid bending activities/lifting heavy weights.
Always use a chair with back support/ when seated foot should be rested on the floors.