Hi sir....      If u have  habits  like smoking,pan chewing kindly quit the habit ...painful mouth opening may be due to oral soft  tissue problem like oral submucous fibrosis, muscle damage, or you may have TMJ problem like arthritis, or due to trauma ,or if you have any recent wisdom tooth extraction....which can be rule out only by oral diagnosis

Hi..it can be solved through Orthodontic treatment only Regards

Go for hot fermentation at tmj joint and go with the exercises

Please see a dentist in person,as I think you may be suffering from oral submucous fibrosis that needs a long-term treatment.