Even if it's a meniscal tear, many orthopods will avoid intervention or even an MRI for about 6 weeks. Give it (whatever it may be) a chance to heal itself. It could be just a ligament or tendon strain, for all you know. That's where the 6 weeks come in. If it's still aching after an adequate attempt at conservative management, then do something about it (i.e. MRI).
Disclaimer: this is an internet diagnosis (you get what you pay for
).