Heel pain is basically due to calf tightness with inflammation of plantar fascia... Most can get managed by plantar stretching and medications. Knee pain has various reason... It could be due to injury, infection or plain musculoskeletal issue based on your young age.
Next Steps
Consult Dr Arvind Vatkar
Health Tips
Exercises, good footware and please consult a ortho doctor is there is fever increased pain