Hi, thanks for writing to HCM.
After going through the description, I feel that you have developed PATELLO FEMORAL ARTHRITIS
(wear and tear in the thigh bone joint surface and the knee cap surface) giving the typical cracking sounds.
One important activity that should not be done is DEEP KNEE BENDING which aggravates this problem.
Avoid high impact sports & Do regular Quadriceps strengthening exercises which help to resolve your issues.
Hope this information is helpful. Good day