How long will it take till my erection fully stops?

hey guys I've started chastity for 2 weeks now but i still can't wear it while sleeping, i also sometimes remove it because of the erections i have while wearing it are a bit painful when i get really horny. is it okay to feel that kind of pain or maybe the cage is a bit big or the ring a bit small?

cause i read a lot of articles that says that it shouldn't be any room for erection in order to not feel the pain but i get erected while wearing it and i can still feel my clit getting hard under there. and if that feeling is normal how long does it take to go away and stop getting erections?

also if i want to achieve shrinkage should i be weraing it permanently? or can i achieve that without wearing while sleeping?