Old deep filling suddenly hurting?

[Methyl Blue]

I've had a deep filling in my lower left first molar for possibly a year or more. Suddenly I am having pain in that whole left area -_- My wisdom tooth is slowly emerging, I saw a black area on my 2nd molar and now issues with the first molar. I thought the pain was coming from the 2nd molar and had it filled. Now I realize that my 1st molar also hurts. When I press on it and chew. It is a minor ache when I'm not eating and don't really notice it unless I focus on it. Could infection have spread very slowly or is it just acting up?
Picture sucks but that huge white thing on the bottom right is my filling from a year ago.

 

[Dr. Daniel]

Hi,

the he main reason for the infection (if indeed it is the case) in the first molar is the big filling.

Certainly there is some connection between that and other teeth but it is marginal.