Very scared - hard lymph nodes

Hey guys,

14 months ago, I first noticed two small marble sized lymph nodes in my neck under my jaw.  They were rock hard and movable but painless.  Obviouslly, I was very scared about lymphoma or cancer.  I went to see a hematologist who had a hard time feeling the nodes (they move around a lot) but sent me for CT and ultrasound.  The CT and ultrasound didn't even say I had swollen lymph nodes but didn't give me any answers.

 

fast forward to last month and the nodes haven't changed but they still remain rock hard.  Now, another node has appeared in the middle under my chin and is very similar to my other two, around 2cm and very very hard but somewhat moveable. My new GP doesn't seem to think it's much, but no one can explain to me why I have these lumps that are rock hard and haven't gone away.

 

i am truly terrified that I have some sort of cancer and am frusturated that no one can tell me what these lumps might be.  Can lymph nodes remain hard and 2cm forever?  I keep reading that lymph nodes are supposed to be soft, but these are seriously like rocks.  Thanks