I could really use some help with latching pain

My left breast seems to have dried up completely and my midwife advises to let it do it's natural thing instead of trying to force more milk out of it. So I'm nursing several times a day and once at night from my right breast only. The nipple is only a little sore, but my son has a tendency to latch on VERY HARD sometimes and also likes to surprise me with the occasional "nipple drag" (yes, that's as uncomfortable as it sounds...!)
If I tell my little one "gently" then he'll usually latch on softly, but if he's sleepy or moody he'll sometimes just chomp down. I've been saying "ow!" so much lately from the discomfort that he'll sometimes pop-off and repeat "ow!" back to me, which bums me out.
I think my milk has decreased somewhat in my right breast as well, so we may be on the road to weaning. But I was hoping to nurse until my son was ready to self-wean, instead of this other route of reduced production and pain.
Any tips or suggestions?
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