I do have the occasional patient who complains that one side was more uncomfortable than the other. It could be that the injection was near a blood vessel, which is usually more sensitive. Also, the nasolabial fold in the nasal area is always a bit more tender during injections. It certainly was NOT due to septum or sinus issues. You may or may not experience the same issues the next time you're injected, but the good news is there's nothing to worry about.
The angular artery tracks through the area of the superior nasolabial fold. If the Perlane injection is placed deep, it may cause compression on this artery and trigger pain. The good news is your injector was using a cannula. The cannula lowers the risk substantially of injecting into an artery which could cause severe problems including skin necrosis. You did not describe that scenario. The pain you describes was probably secondary to compression on this vessel.