Hi,

consider that lymph nodes usually swell up due to infection and can remain swollen for quite some time after. It doesn't mean anything is wrong with you. 

Statistically it's more likely to be that than something serious. 

No one on here can know for sure but you can make an appointment with your gp and have the lump examined if you're worried it might be something bad. That's the only thing you can do. 

You seem to be having other issues as well at the moment so I'd get checked by the GP if I were you. 

I have 2 on my neck and went to the GP this week. I'm having a blood test done next week but she wasn't too concerned. I had no infections at all unlike you and have had them for weeks. 

Good luck!