I suggest getting in to see your primary care doctor
to diagnose what is going on.
The most likely possibility is that you have a throat infection. Most throat infections are caused by viruses, and they lead to swelling of the tonsils as well as the lymph nodes in the neck. This is a normal part of your body fighting off the infection, but it can be uncomfortable. and lead to the sensation of a hard lump like you are feeling.
Occasionally, throat infections are caused by the strep bacteria. This is important to differentiate because the strep infections should be treated with antibiotics to prevent complications, including inflammation in the heart. Your doctor will be able to determine whether the chance you have strep throat is high enough to merit treating with an antibiotic or they may perform a test to see if you have the infection.
Rarely throat infections can be quite serious and require more emergent treatment. You should go to the emergency room if you have very high fevers or if you actually are having difficulty swallowing (other than just having pain) your food or saliva, as these can be signs of a more serious infection.