That's not good, I never get bugs in my soil, soil should be sterilized so you do not get bugs or weeds.
Even sterilised soil is susceptable to spring tails, they are benificial bugs. The soil starts of sterilised, sits in a warehouse, travels hundreds of miles to another warehouse with lots of other soil and then gets taken to a garden shop or hardware shop where they either stack it outside before bringing indoors or if your lucky put it straight on to a clean dry shelf.
Bugs are evrywhere, you cant stop them getting into the soil at anystage of the process, its to be expected, my garden centre has a lot of outdoor plants for sale and bugs are present everywhere, dosent take much for them to find a nice bag of soil to breed in.
Some bugs are not pests in soil so try check which ones you have, the very small ones need magnification and there are sites you can post the pics on to get an accurate identification of species and family they belong to. This is the point of organics, you want some bugs. Springtails rock and help fix nutrients for my plants otherwise unavailable, there are many other small bugs that are good too.
Springtail so named cause its defence mechanism is a small apendage under the abdomen that allows them to jump/spring to a safe place, easy to identify, lots of small white bugs in soil and runoff that jump everywhere. Peace