I used to get that, caused by a badly fitting saddle.  It was too wide to support my sitbones therefore I used to slide forward onto the nose of the saddle and the soft tissue.  A fair bit of trial and error later I've found a saddle that works for me (a men's flite), in fact I'd like to try an even narrower saddle.

I agree with Limey Slime about firm saddle being better, particularly if your doing long miles and I've had a quick look at the SMP saddle and it is the kind of thing I actually would go for (thanks Limey Slime, will have a good look at the,) and it comes in several widths.  Saddles are very personal though and what works for me may be hell for you, if you don't have many female friends who ride and who's saddles you can try then it can end up an expensive process to get one that suits you (been there).

A start may be to go to a Specialized dealer and sit on their butt-ometer which will measure the gap between your sitbones, you can then look at saddles which are designed to support your sitbones properly.  There is no point being on a wide saddle when you have narrow sitbones.

Shorts can also make a difference, I have practically no problems with my Sugoi shorts, the chamois just seems to suit me - I now won't wear anything else on rides over 1.5 hours which means I have several pairs of expensive other brand cycling shorts that hardly get worn now.  I will wear Assos chamois cream on longer rides but you have to be careful where you put it as its got menthol in it, if I've not been doing many long rides and my butt has softened up a bit  then I will sometimes use Sudacreme or similar after the ride though I don't have problems like I used to with bad saddle/short combination.