Hi, Thanks for writing in. Lower back pain after spinal tap is a known rare complication causing distress to the patient. It occurs in 0.3% of lumbar punctures and you might be one among them. This is essentially due to nerve root irritation during putting the needle in the spinal space while withdrawing the spinal fluid to check for meningitis. This pain can also be accompanied with headache. The pain needs symptomatic treatment and can last from 8 days to a year after the spinal tap. Please try using heat pad or doing physiotherapy to get relief from the pain. Avoid doing heavy physical activity or lifting heavy weights or making sudden back movements. Use applications containing pain reliever and muscle relaxants for reducing the pain. If pain persists after a year of the procedure then consult a pain clinic doctor.