Yes, it seems that you've touched a swollen LYMPH node. Lymph nodes are in charge of producing lymph, which travels throughout your body in the lymph system, and filters impurities from the body. So, they're working overtime when you're sick to get you better. When swelling appears suddenly and is painful, it is usually caused by injury or an infection.
Lymph nodes do become painful to the touch, and can become hard, but if they don't return to their normal size after a couple of week, you should contact your physician. Lymph nodes are located all over the body, but in the neck, there is a chain of lymph nodes on either side of the front of the neck, both sides of the neck, and down each side of the back of the neck.