Hi,
Firstly, being on the lighter part of the day, if you are 10.9 ft..Try your chances to get into Guinness book of World Records.
what appears to me, your problem can range from minor quadriceps (front muscle of the thigh) strain, to a little to worry pes anserinus tendonitis/bursitis..to a more complex problem Chondromalacia patella. To rule out an experienced musculoskeletal physiotherapist near you can help. Without evaluation/ examination it's really difficult to say.
Next Steps
consultant a musculoskeletal physiotherapist or an orthopedic doctor before resuming your aerobic classes.
Health Tips
Avoid painful activities, apply ice 2-3 times and pre warm up and post Colling down techniques must be followed with every aerobic session once you recover from your pain.