Question: This morning, I noticed sensitivity in two parts of the front of my neck when using my electric shaver. I'm wondering what the cause is, and, as a worrier, I'm wondering how likely it is that it might be a sign of cancer. I've linked pictures at the bottom (the soreness is where my two fingers are) but I'll give some more information. It also is a little sore if I fully extend the neck (as if I'm looking up to the sky). I had something similar in April, and I assumed it was because when I'm stressed, my neck twitches. It had been twitching in April. So that's what I attributed it to then. However, it hasn't been twitching now but I did yesterday increase the weights I was using in my upper body exercises. It wasn't a lot of weight but it was more than I am used to. Could it just be a muscle strain? If it was cancer, would the soreness be unlikely to have disappeared in April and then come back this morning? Or could it be swollen reactive lymph nodes and a sign I'm getting sick? Thanks for your help.
Pictures:
https://www.dropbox.com/s/btp9u8dj9kch049/IMG_8015.JPG?dl=0
https://www.dropbox.com/s/073bd9gtg0tbndl/IMG_8017.JPG?dl=0
Note: The soreness probably extends a little further up (right to the lowest part of the jaw bone).

I just wanted to add that I do not feel a lump or growth. Also, it is hard to describe the feeling in the neck but it is a combination of mildly "sore" and "tender."