Hi, I had an mri a few weeks ago for an enlarged tonsil and some lymph nodes, also prior to the scan I noticed a large oval shape firm lump on left back of neck. It does not protrude and can only be felt if I press it or when I turn my head to side or tilt it back or lay on side. My mri came back as normal with no abnormalities. They put a marker where the lump was for the mri but still nothing shows. However I can feel the large lump and it worries me every day. I cry and google constantly as I already suffer from health anxiety. The consultant who gave me my results said he thinks it coyjd be a tendon. 
I've even asked for an ultrasound but consultant does not see this as beneficial as mri didn't show anything so now I'm going to speak to my gp next week about it all. I'm just so worried as surely it must be something? Could an mri miss a lump? Or is it likely it is just muscle?! I'm having my tonsils out next month and they will look at lump again then.