First, I agree with TwistedMane.
Anyway, unless it's usual for you to have two extremely different curl patterns on your head, you're probably right: it could be caused by some sort of damage, whether that be chemical, heat, stress (pulling/brushing hard over time) or even a severe dietary; hormonal or medical change you're undergoing.
That the pattern is looser only on one side, seems more suspicious of environmental damage. If you can help it, I wouldn't apply heat to the side that's straight cause you don't want to compound any damage.
I'm about to post info on a way to set hair so that the curl is more blended - it's a heatless set. I'll try and have that posted w/in the next two days, in this forum ("General Discussion about Curly Hair").
Still, doing the following might help to some degree:
First, clarify your hair with a clarifying shampoo (It will contain sulfates, which is okay for this once in a while procedure). Second, apply a protein reconstructer (It's a deep treatment that you leave on for about 30 min.s - Aphogee or K-pak are both decent options, but there are others). This will help fill in any "gaps" in the cortex of damaged hair, strengthen your strands, and promote better elasticity, which in turn will promote better curl. Third, follow that up w/a moisturizing conditioner (leave in for about 30 min.s and rinse). Fourth, do an ACV rinse, either before or after using your conditioner. That helps restore your hair's pH balance and closes the cuticle some (increasing the integrity of the curl and promoting shine). You may have to repeat this process over a few weeks, but that may help your hair improve. You might also benefit from frequent trims for the time being - gradually getting rid of possibly damaged hair.
If you have decent length, here's something you could try too, in terms of balancing the curls on your head: After you've washed/co-washed, use a LI and/or some gel, then place your hair into a couple of loose braids and dry them overnight. (You can sleep w/a silk bonnet for protection, if you have that.) When you unbraid your hair, your wave or curl pattern should be more consistent throughout your head.
Last edited by Korkscrew; 01-20-2013 at 05:43 PM.