The answer to 'why is my tick scratching sounds' is that ticks do not actually make scratching sounds. Ticks are small parasitic insects that feed on the blood of their host, which is typically a mammal, bird, or reptile. The scratching or biting sensation you may be feeling is likely due to the tick's feeding behavior, not an actual audible sound.
Ticks latch onto the skin and insert their mouthparts to feed. This can cause an itchy, irritated feeling that may lead some people to think the tick is making a scratching sound. However, ticks are generally silent and do not produce any audible noises. The scratching sensation is simply a symptom of the tick's feeding process.