I have a night splint for plantar fascitis... keeps your foot at a roughly 90 degree angle to keep that tendon a bit looser.
Another home remedy is to roll a golf ball under your foot, you can do it at your desk at work if you want.
Note: I don't have plantar fascitis, I had side effects from getting a plate put in my foot that were similar so I couldn't tell you if that's what you have.