That is probably not you ( and I say "probably").

Is the sound happening under-the-chin ?  Does a listener hear it ?  Or do you hear it when recording ?  What do you hear if you prop the violin on your knees and take some slow (careful) strokes on the open strings ?  Under-the-chin can be very deceptive and throw off intonation also.

The stock answer to your problem is to take it to a luthier to reset the post. That might work, or NOT.  Some violins are noisy in the treble.

Does your environment have extremes of temperature and humidity.  This can play tricks also.

You may get some relief with a different bow.  (Run down to your local bow store

Try quieting the sound with a little Tourte mute on the "A" string.  (Some fiddlers actually put a spring cloths pin on the bridge.)

May the force be with you.

PS  I forgot.  Keep your strings mostly clean.   Run your fingernail along the string to eliminate rosin bumps.  Don't use alcohol to clean strings.

Cleaning strings with a micro-cloth or something similar is only a very limited cleaning. 

The rosin that makes bad noises is stuck on the strings as a collection of tiny rosin drops which interfere with the bow/string interface.  The bow actually melts some rosin and a "splash" happens.  You can finger scratch the splash even 1 or 2 inches up the finger board.  You can also see the splash with a magnifying glass.

The sound gets raspy when this layer of rosin slurry gets too thick.