I soak em occasionally in water as hot as I can take it with Epsom Salt. Also, occasionally, I'll have my Wife rub them but not in a soothing way. She will mash with her thumbs on the sore spots. Sometimes, it flat out hurts but it sure helps my feet loosen up. OH! A third thing.......The past 6 months, I have worn Sketchers shoes. THEY ROCK!!!
I have always had big and flat feet that never bothered me till my late 40s. I swear, sometimes the tendon that runs across the top of my right foot makes my foot feel like it's broken at times. I believe shoes are a key factor. Sketchers are the best I have ever had. Nike? I will never wear those again.