Hello,
How long you have this pain?
Diagnosed by clinical examination or MRI?
Patellar tendonitis is a challenging conditions to treat.
Traditional therapeutic approach like ice, Anti inflammatory drug, Ultrasound, IFT and stretches will not give any results for sure. Do not waste time.
Next Steps
Consult a sports physiotherapist.
Eccentric quadriceps exercises is the answer for your problem. But make sure you train your entire lower body muscles.
Health Tips
Avoid Running, Jumping sports for few weeks.