Hello,
Welcome to ehealthforum.
There are various causes of painless lump in throat and viral or bacterial infection is the commonest cause which can cause enlarged lymph nodes.
Thyroid gland may also produce lump due to any thyroid disease. Lumps present in the skin or below the skin can be because of cysts like sebaceous cysts.
It also depends on various factors as the size, shape,consistency,any increase or decrease in size,pain and location.
Since I am not examining you it is difficult to comment upon.According to the symptoms you describe( painless, no change in size) it seems like infection. You might consider getting it examined after few weeks and may go for investigations like biopsy which will help to confirm the diagnosis.
Hope it helps.
Take care!