Thanks for being with HCM.
Sudden Onset of back pain
In 20 years female could be due to
2- Just a muscular back pain
3- Mechanical back pain
4- Vit-D deficiency
5- Prolapse intervertebral disc
(less like in your case) in that generally patient has radiating pain
in lower limb/s
Due you have any sudden jerky movement while jimmying or have suddenly lift any heavy things?
I would suggest to take an opinion of an Orthopedician for better clinical correlation and
to get a X-ray sacrococcyx region and Vit-D levels.
For pain relief you can apply hot fomentation and nise gel locally and mild anti inflammatory like Aceclofenac
For more queries you can write to us.
Wish you good health.