afedorov:
I thought maybe it is FLUX some how connects neighbor pins...
So did you use flux? You shouldn't have to use ANY flux for this job.
If you did use acid flux, then throw it away and start over.
You should use normal rosin-core electronics solder. Nothing else.
Your pins are badly soldered.
Try this:
Hold the soldering iron to the pin AND via for two seconds (pre-heating both).
Then apply solder to the pin/via (not to the solder tip), until it flows inside the via (2-3seconds).
Hold for another second, before removing the tip quickly.
Leo..