Its because of muscle weakness which becomes due to overuse of muscles over time. You should consult a physiotherapist.
Next Steps
Go to a physiotherapist.. Ultrasonic therapy +IFT +Heating therapy +some strengthening exercises as well as stretching exercises will be helpful for sure.
Health Tips
At home.. Rest +hot water fomentation +pain killer gel +no long sitting /standing /travelling /driving /walking /stair climbing /computer work /table work +no cold exposure +no manual exertions +no weight lifting +correct posture (sit tall) +use back rest & foot rest.