I"m not cathe but here's some things to consider.
1st - check your neck, spine, hips, and ankles for any stresses. Un aligned hips or an unsupported back could cause knee issues. When i have knee pain, i try to pop my spine from neck to hips ...and sure enough, i usually hear bubble wrap pops. Alot of pple think that knee pain is a knee problem...i tend to believe that alot of knee pain starts with a stressed spine and core.
2nd - Palpitate (feel) the area around the knee and see if you feel any tenderness or inflamation. Feel around the shin area.
3rd - If you do alot of step, you probably have a little bit of a muscle imbalance in that you probably have strong tight quadriceps and weak hamstring muscles. THis is very common with women, making them suseptible to ACL problems. High step exercises and plyo metric exercises can help, just make sure you *REALLY REALLY* focus on controlling, tightening the hamstring as you work.
4th - Make sure your are adding lower body stretching into your workout routine - especially for the quads and hamstrings.
5th, when doing hops, turnsteps, hop turns, richocetts, etc...make sure you are really unloading off of that foot, and you're not twisting your knees at all.
6th - Go easy on the cardio for a week, and focus on strength training workouts.
7th - has it been damp or rainy lately? Maybe you have a touch of joint stiffness or mild arthritis in the joint? I know my knees tend to get sensitive on damp/rainy days.
Hope that helps for now...of course, if the pain persists, see a doctor.