Yup u have to take rest for few days...because in sprains or sudden pain like in ur condition it involves muscles in it and the best way to treat these muscle pain is to take rest along with some medicines because we dont want in future to exceed these condition and to face more problems...and i will advise u to dont take pain killer for these i will give u temporary relief but worsen ur condition..
Next Steps
1.Trayodshanga Guggula 2 tab twice a day
2.Dashamul kwatha 2 tsp twice a day
3. Mahanarayana taila for local application and then hot fomentation over there...
Health Tips
These injury will not be of sudden as ur job is u r instructor so there may be a chance of past small injury now its causing more problem...
make an habit after ur fitness session at last before taking a bath apply and til taila over your body and then take bath after 10 mins these will help u to avoid these kind of problems in future...