I got my nostril pierced in may, i ordered the steel ball screw from BAF and was pierced with it. My nostril is taking a very long time to heal, its been about 5 months, almost 6 since I've had it. the side of the hole on the inside closes really fast. in the time it takes to switch jewelery, its already closed, and it hurts getting it back in. i have a nostril piercing before and it went fine and i don't know how this is taking so long to heal. any advice???

 nostril piercings (as well as any cartilage piercing) can take up to a year to fully heal.

 give it time, and continue to treat it like a fresh piercing.

 Which nosescrew was it exactly? The material might be causing you problems, or the bend if it was a pre-bent might not fit well. 

I'd recommend buying an Industrial Strength titanium straight nosescrew, then taking it to your piercer to be custom-bent to fit your anatomy. Titanium is higher-quality than stainless steel, so if there's any irritation going on due to the material, changing to titanium should help. You might want to consider either a halfdome (I love these!) or flat disk nosescrew rather than a ball since it'll get caught on fewer things which should also promote healing.

I'd also continue to do salt water soaks and try not to fiddle with it too much (as one person said, treat it like a new piercing). if that doesn't work, you could also look into stretching up a size (especially if you were pierced at 20g). My nostril piercing is 20g and I haven't had any problems with it; I know people who were also pierced at 20g and their body didn't settle down and accept the piercing until they stretched to 18g. If you you stretch (or are already at 18g) could could also look into Gorilla Glass' glass nosescrews; again, glass is a very good material for healing.

Good luck! : )

 As others have said, nostril piercings can take a LONG time to heal.  You should not be changing the jewelry before 5 months.  I did change my jewelry too soon and got an oozy bump because of it that set my healing back even further.  I'm not sure exactly when you changed it or how many times, but I can definitely see that irritating it.

Baby it, try not to touch it or get it caught on your clothes.  If you have high quality, appropriate for your anatomy, jewelry in there right now I would NOT attempt to change it for several months.  If you need some better jewelry have a piercer put it in and and then don't change it for months.

 They do take long to heal but once my nostril piercing was healed I had no further trouble with it, so there is light at the end of the tunnel.

 Another chime in for the be patient and give it time school of thought.  I am healing a nostril piercing too..  healing cartilage piercings require patience. Heck, I pierced my freaking conch last SEPTEMBER and it's just now getting close to what I would call healed.  

my nostril piercing healed quickly with a nose bone and lots of sss.