You may feel better with your TSH a bit lower~~ around a 1-2. When my TSH came down to 2.9, my dose was increased by 25 mcg. It made a big difference in my symptoms.
Synthroid can decrease the size of goiter/nodules, but it will take a while for that to take affect.
I agree about getting an ultrasound.
Very common to have this symptom. But I have to ask a few thing. How long were you on generic ? When did you make the switch? and how long has it been now that you are on Synthroid?
I am leaning to belive that you might not have given yourself enough time yet. But if you seem concerned as I was recently - get an ultra sound(My advice - of the neck AND thyroid)
That will rule 99% whether you have nodule or not. No- they can not always be found with a neck check. I know.
The gland can become swollen or enlarged sometimes. but again if you have had a through neck check that would be found.
If possible answer the questions above - If i catch it before I leave today. I will answer back.
Good luck