Originally Posted by HigherGround

Raising the saddle may have contributed to it. I had a similar problem after having a fitting done at a local bike shop. It also recurred last year when I was doing a lot of weight in the gym on the back extension machine, and a lot of riding (by my standards).

I would suggest lowering your saddle to the original height, and once the pain subsides, try moving it up very gradually again. Starting a stretching routine may help as well. Icing after rides would probably be a good idea as well.

I've read that a seat position that is a bit more forward may be beneficial for people with tight hip flexors, but I haven't really seen a consensus on it.

I hope this helps!