The aches are good aches I keep telling myself...
I've been mainly focussing on flows for athletes so far with the glutes, hamstrings and hip flexors being my tighter areas. As I've held poses such as pigeon I've really felt the stretch and once I release, the lengthening of the muscles is really noticeable... as is the ache the next day! It's not pain, it's just my body noticing that I've done some yoga and feeling the lasting effects. It certainly feels a bit odd sometimes though!
Large amounts of my practise is based around pigeon, low lunges, the warrior sequence and flying pigeon (or 'standing figure of four' as I remember it!). I'm very stiff and tight in the glutes areas and a LONG way from finding these poses comfortable! It's often frustrating and difficult to keep your mind away from the VERY bendy yogis who can touch the floor from flying pigeon, or who have easily square hips whilst holding pigeon. So jealous! It's important to remind yourself that it isn't about the result, but the effort and intent behind your practise…as difficult as this may be!
I can't say that I'm feeling any more lithe and flexible as yet, but good things come to those who wait as they say! The main effect that I'm receiving at the moment is a lighter, almost relived sense in my back. Where I used to have an odd nagging pain, I now have relief and almost an 'empty' feeling. It's amazing how everything is all tied together and the knock on effects of stretching one section of the body can positively impact on other areas.
Clearly your muscles are just like an elastic band, the more you stretch, the looser and more stretched they become. This means that the tightness will reduce hopefully and the ache might disappear. I'm starting to quite like that feeling now though so I'm happy for it to stay- it makes me feel like I've worked through a good session!