Why is my knee bone hurting post-surgery?

I suggest that you see your orthopedic surgeon right away. Lachman is the presence of a failed surgery or weak muscles. Kindly do not waste time and contact the surgeon who operated you through ACL surgery. 

You may be suffering from crepitus, a condition involving joints made from popping or cracking sounds. When the knee or another joint, like the knee, expands, you can hear the sound. This says that sometimes air bubbles may be in the joint space. Or the Cheerios cereal-like cartilage surfaces of our bones are responsible for creating noise.

You might have had a pneumothorax, which happens when air gets into the space between your lung and chest wall. This can occur with a sudden chest injury or the rupture of a tiny air sac. The swelling in your armpit could be connected to this. To receive appropriate care which may include releasing pressurized air by draining it out to facilitate lung expansion.

Its not like that. Any selective Cox2 inhibitor will do the job.

You have patellofemoral pain syndrome. This condition causes pain around or under the knee cap, which can spread to the side of the knee. It's often due to overuse, weak muscles, or improper knee-cap positioning. Exercises to strengthen leg muscles and supportive sports shoes can help. A key part of treatment is avoiding activities that worsen the pain.