Dear,
Firstly you should take a rest at home for a few days and what was your position during stretching? It may be the refer pain of low back pain. Can you sit and stand for a long time? And can you walk for a long time also? If you suffer from aching pain or tingling and numbness sensation in your leg during walking, you should go and see the physical therapist. You should get physical treatment such as electrotherapy and lumbar traction for a few weeks and if not you should lie on hard matress in crook lying position with pillows for a few days and you should apply lumbar corset during sitting, standing and walking position. You can use hot packs for 15 or 20 minutes, 3 times per day for your painful area.
yours sincerely,
THIRI NWE(Physiotherapist)