Sounds like your pipes were assembled on the bench, tightened up, and then transferred to the bike. If they weren't assembled in the exact position that will fit your Raider, then they will never fit right.
Loosen everything. There's usually a clamp holding the header section to the tail pipe section. Make sure it's loose enough to allow the 2 sections to slide onto one another. Once everything moves freely, start snugging down everything. Go progressively, and wiggle parts a bit between each round of tightening to help them settle in the proper position.
Hope this solves your issue.