Some things that might help: doing some muscle-strengthening exercises. When I was getting really bad shin splints, I did these exercises after every run. Finding a similar set of home stretches and exercises you could do after your runs might help.
Increase your cadence. A tactic I've used both when dealing with recurrent knee pain and with the aforementioned shin splints problem. A higher cadence can help reduce the stress on the joints. I typically run about 170 spm, but tried to keep it up over 180 while recovering.
New shoes! Older running shoes lose their cushioning. If you've done more than 1000 km in the shoes you're currently using, strongly consider a new pair. And consider whether they're the right type of shoes for you. You don't want carbon super shoes for your daily drivers—save those for the race and just one or two runs to break them in before the race. Nor do you want track flats if you're running on the road or a trail.
Combine with cutting back the distance to the point that you don't feel the pain. Pain in joints is very, very rarely the sort of thing it's a good idea just to "run through". "No pain, no gain" works for the sort of pain you get in your lungs when doing a really hard interval session. It does not work here.
Most importantly. If you can't get yourself pain-free after reducing distance and slowly, slowly building the distance back up, along with some other basic ideas like the other ones I mentioned and the ones other users here have mentioned. Go and see a doctor.