Generally speaking you are allowed to work in Switzerland without restrictions but you do need to get a permit to work for more than three months. See https://www.ch.ch/en/working-switzerland-eu-efta/
Note that while Switzerland is covered by the EU freedom of movement, it's not an EU member and only implements these rules via a special agreement. Because of this, the transition period for Bulgarian and Romanian citizens lasted until mid-2016 (as opposed to 2014 at most for EU member states) and Switzerland still has the right to introduce a quota until 2019 if there is a large increase in the number of Bulgarian or Romanian citizens coming to the country (it's the so-called "safety clause", which also applied until 2014 to all EU citizens). Right now however, there is no such quota (the next review of the situation is planned for May 2017).
Finally, the Swiss people voted three years ago to limit immigration in general which seemed to set the country up for a major clash with the EU and could have consequences for EU citizens living in Switzerland. But the federal council (which is tasked with implementing the decision coming out of the referendum) announced earlier this year that it would first seek very modest measures and steer clear of any binding quantitative limit in an attempt to avoid endangering the relationship with the EU. Whether that's enough to keep the agreement alive and/or satisfy the voters and parties who are unhappy with the current situation remains to be seen.
Given all this, if you are specifically interested in securing a future for yourself in Switzerland, it seems like a good idea to move as soon as possible. Should any restrictive rules be introduced in the coming years (either within the framework of the current agreement, through a new agreement or outside of any agreement), you would have some hope to be in a better position than those trying to enter afterwards. It's obviously not guaranteed but not altogether unlikely that any more restrictive system would come with exceptions or transition rules allowing people already in the country to be grandfathered in.