My 4 year old is going through something which has me concerned and I don't do't if is is something serious or not. About two months ago he started to constantly go "hmmm" when at rest, i.e. watching TV or in the car. At the same time he was lifting his chin like he was stretching his neck. I took him to the doctor who indicated it may be a nassel drip and prescribed a spray. The "hmmm" is not happening as frequently but he neck stretching (chin lifting) has gotten worse. He now also pulls his chin down into his chest and lifts his shoulders...it is especially bad when he is eating. He recently (about 2 months ago) hit his mouth hard on another boys head...maybe somethings in his neck or jaw was injured. Any advice...it is very concerning.