Sweden has rent controls, which has caused long queues to apartments (we're talking wait times of 20 years) as well as a significant grey/black market in second, third and even fourth hand contracts, because the regulated first contract is so valuable that people keep them and rent them onwards.

It has also created situations where e.g. trade unions and other organisations (who own rental apartments) arrange nicely-located apartments to friendly politicians (and their relatives) ahead of the queue at very advantageous rents.

Local municipalities have veto rights to block development. There are also a bunch of rules, often overlapping, than may stop planning. All planning decisions can also be (and are) appealed for years.

There is also a lack of cheap housing, most houses built today are unaffordable to most low/medium earners. This has become an even more acute problem with the recent influx of refugees. This has lead to overcrowding in poorer suburbs.

Contrary to popular belief there is no housing shortage in Sweden. There is howere shortage of new cheap housing.