Alright, walters, you've asked a reasonable question this time.
First, based upon your description, you're not really doing anything wrong. What you're doing is called "Mixing"

. And when you have a lead vocal that has to stand up in front of who knows how many other tracks, it's not unusual to have to drop the backing tracks a bit and bring the vocals forward some.
That said, though, making multiple copies of a track to boost the gain is really no different than just boosting the gain on a single track. You shouldn't have to do the multiple tracks thing just to get volume. So here's a couple of things to look at:
First, make your you have the gain staging set up correctly when you're recording the vocals. Is your mic pre putting out something close to 0VU on an average? How about anything else like a compressor that you may have in the recording signal chain; are you compressing but not applying makeup gain to return the average tracking level back up to nominal line level?
Speaking of compression, that the second thing to look at. If your vocals are on the dynamic side, you might need to add a little compression to them (not too much) to tighen them up and give yourself a lttle more headroom on the track so you have a little more room to apply some extra gain.
And finally, don't be afraid of turning down the backing tracks, They don't need to be riding at anything near their full volume capacity. Turning down a few tracks in order to make room for a lead track is often a better idea than trying to push the lead track too hard. If you feel your mixdown is too quiet, you can always make up for that by tweaking the mixdown.
Now see, Wally; you ask a reasonable question and you'll get a reasonable answer. Simple, isn't it?
G.