keeping up with exercise

have a prob keeping up with my exercise regime due to rain & leg pain. was due to start my tennis course this week but it was postponed due to rain. stopped my brisk walking caused i realise my leg tend to tire easier when i walk on the normal ground then on treadmill and the soles of my feet seem to hurt lately. wondering whether its due to "excessive" exercise nowadays or it is the prob with my shoes? the shoes were bought 2 yrs back & was only worn once (bought it for amore women's day out :P).. shoe itself is in good condition, i.e. the sole hasnt come off yet after my numerous exercise sessions. wondering whether it could be the sole had "harden" so it has become not so comfy to wear? think i shall ask the doc when i go for my second appointment this friday.