I squat and deadlift heavy, and for the past few months have been experiencing plantar fasciitis in my left foot recurringly (noticeably after I took up front squats, cleans, and push presses regularly, since I haven't made gains on my lift much). I have flat feet (used to run in cushioned shoes) and after 1.5 years of heavy lifting am still flat-footed. Does anybody have any tips on how I should go about healing my inflamed tendon, and strengthen the area at the same time? I would like to continue to lift heavy in the future.

Thanks in advance!