My almost 7 yo son has constant sniffing, throat clearing, and mouth stretching. his pedi has told me not to worry but its been over 6 months?

Could be allergies: Are causing his nasal drainage (which causes throat clearing). Environmental allergens (molds & dust are noticable during winter months, and you've seen his symptoms for 6 months), but foods can also cause similar symptoms. I often recommend the airfree purifier to eliminate mold, homeopathic mold and dust remedies, and if foods are the problem, eliminate wheat and dairy for 2 weeks then challenge.