(Concern) Pain along the left side of the neck lymph nodes

Recently, starting from below my left ear, I feel like the left lymph node area—I'm not sure if that's the correct term—appears slightly swollen in a round shape... and I also have pain.

There is no pain or swelling on the right side in the same location.

If you don't touch it, you won't feel much pain, but

I am experiencing pain that continues to be noticeable.

Should we perform detailed tests such as a CT scan?

And which department should I go to for treatment...