Cracking sound which comes on clenching jaw could be a feature of TMJ arthritis
. Later on pain could develop and make it hard to open the jaw.
The lump which moves in front of your right ear is a muscle called Masseter. this muscle is present in everyone. It helps in clenching the jaw and chewing food. It is normal, nothing to worry.
This could be due to malocclusion
problems in the teeth of your jaw or other causes of arthritis. It is best you consult a Dentist
as they will be able to find the root cause of this problem and decide the right management.
Wishing good health.