When I had that issue is was because the saddle I was riding was too pear shaped (gilles berthoud aspin), once I switched back to more of a t shape the problem went away. As soon as my foot heals I am going to try a Selle An-Atomica but at the moment I am on a fizik vittesse sport (old one) some women hate them but it fits me perfectly. Am assuming you have looked at all the fantastic saddle posts? Have you measured sit bones?
Sky King
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Gilles Berthoud "Bernard"
Surly ECR "Eazi"
Empowering the Bicycle Traveler
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