Hi there, i have a vein or artery sticking out in my palm near my thumb and it is painful but there is no discouloration nor warmness.

Probably not a clot: It is almost certainly not an artery but palm veins sometimes are prominent. If it is not hard to the touch then you probably don't have a blood clot, which is relatively rare there anyway. It could be an inflammation of the vein (phlebitis) or perhaps it's the underlying tissues that are irritated. If it persists more than a week or two, then your family doctor can help diagnose the problem.