I have round raised ulcers/bumps with little red heads which swell on my mouth palate?they are only painfull when they swell?

Although its: Difficult to say for sure, this sounds like inflamed accessory salivary glands. You need to have your dentist or an oral surgeon look at these bumps and explain them. A biopsy may be indicated, but don't fret. See about this soon.

Probably mucocele: Small salivary glands whose ducts have been traumatized. Have an Oral Surgeon look at them when they are active. They may not need treatment unless irritating.