Hello,
is there any problems if simultaneously using software and surfing eBay?
Does software login to my eBay account all the time while i use it or it's login just for time to snipe?
Because i hear that eBay may ban account if it active from different IP's in short time and if these IP's are from foreign location.

Theoretically (and practically) you can browse eBay and use the sniper at the same time.
However, there are few users reported that you better log out from eBay when browsing to avoid issues.
I personally never had any issues with it.