Whenever i yawn, the following happens 1) tears start flowing from my eyes 2) my nose gets blocked and gives an impression that i have a major infection or allergy. nasal passages gets filled up. any reason for this and should i be worried about this?

More info needed: An ophthalmologist would need to know more details like when this first started, how long each episode works, what makes it better, does anything else provoke an episode, etc. An exam, including observing an episode, observing tear drainage (with dye), and a nasal scope may be helpful. From there a trial of medication or imaging may prove helpful. This unusual complaint should be investigated.

Yawning: Yawning causes the glands in the eyes that produce tears to be squeezed resulting in tears that drain into the nasal canals leading to a runny nose. Often the eyes close with yawning further squeezing those tear producing glands. Don't be concerned about this reaction.