Thanks for asking the query,
Red bumps at the roof of the mouth or palate
that are not painful, suggest swelling of minor salivary gland
, there are many minor salivary glands in the palatal area that may get blocked or swell.
Inflammation of the salivary gland due to bacterial or viral infection also leads to formation of lesions.
Other than this the swelling at the roof of mouth can be due to vitaminB12 deficiency, tobacco use, smoking
, low immunity, bacterial or viral infections.
I suggest you to consult a Dentist
and get the examination done.
Hope this helps out.