Two red lump at back of throat (pharynx) approx 2cm and 2.5cm in size. smaller red lumps with similar looks at back of throat also. what is this??

Cobblestoning?: Really hard to say without actually looking in your throat. I would recommend letting your doctor take a look. A common condition that causes raised patches or "lumps" in the back of the throat is pharyngeal cobblestoning. This is caused by islands of prominent and inflamed lymphatic tissue, and typically goes along with either allergies or laryngopharyngeal reflux (acid reflux into the throat).