Postural Correction- Sit Tall, Walk Tall. Extension Exercises x 15 times x twice daily - lying on tummy, take left arm up for 3 seconds, then bring it down, right arm up for 3 seconds, bring down. Bring right leg up, hold for 3 seconds, bring it down. Then right leg up and hold for 3 seconds and bring it down. Repeat twice a day- 10 times. Bhujang Asana -- Lie flat on your stomach, keeping the palms out, bend the neck backward, take a deep breath and while holding it for 6 seconds, raise the chest up. Release breath and relax your body. Repeat the exercise 15 times twice daily.

It appears that you have pulled a muscle while working out. If your pain is limited to the bacl area only, then this is only a pulled muscle. If there is any pain down your leg, then there is a possibility of a slipped disc. Take painkillers, keep mobile and use a hot pack on your back to relieve the muscle spasm.

Consult nearby orthopaedic asap

Take muscle relaxant zerodol th 8mg twice a day for 5 days and then start with back strengthing exercises. Sending you the link of the same https://play.google.com/store/apps/details?id=com.backpainrelieving.backpain Or you can search " back pain relieving exercises by kavin khatri " on google playstore