Hello Bob,
A tardy Welcome to the Pain Management Forum. I am glad that you found us and took the time to post... but sorry to hear about your continued knee pain.
It's been three weeks and apparently nothing you have tried has been helpful. It's time to seek a medical evaluation. I 'm sure that's not what you want to hear.... sorry!
A "pop" could be the meniscus, a ligament or possibly a tendon. Whatever the injury it appears to require more then you are able to do without medical intervention.
I'm guessing your Physician will begin with the least expensive route and x-ray the knee. However you will likely require more detailed imagining such as a CT or MRI. The sooner you get the right diagnosis and proper treatment the sooner you can begin to heal and return to normal activities.
In the meantime I would rest the knee as much as possible and not do anything that aggravates the injury. In other words don't do more damage. I hope you'll keep in touch and let us know how you are doing.
Take Care,
~Tuck
You can try ice first and then heat. Also you can use ibuprofen to alleviate any inflammation. If it has been hurting this long, you should probably go see an orthopaedist. I've seen people walk down the street and blow our their achilles tendon. Never know and better to err on the side of caution.