OK, I'm being a bit difficult here but there's actually little to be said for stretching and massage, at least in the context of fit, well adjusted bodies playing sport. Disclaimer: I'm not a doctor of anything, medical or otherwise, but I ride and I have an opinion based on both practice and research. Let's start with stretching.
Unless you have a lack of flexibility, relative to the range of motion required, what are you trying to achieve by stretching? A warm-up? Why not just ride easily and gradually bring yourself up to speed? In this way you warm up exactly the muscles you need to engage in the activity. Why indeed would you stretch cold muscles and tendons, and thus risk injury? Or perhaps you want to cool down. It seems odd that an activity that is used to 'warm-up' is also used to cool down. In fact why not just ride slower and gradually bring yourself to a cooler state?
If you do have a lack of flexibility then sure, work on what the problem may be with targeted stretches. get advice from a physio on exactly what to do and help to avoid injury.
Which brings me to massage. OK, the pros do it so it must be good. Well maybe it is but where's the evidence? Go on, take a look at the literature. It certainly doesn't seem to hurt, but at best it simply feels good and may act to help convince you that it is good; and thus convinced you may ride better next time. So it's in the mind, not the body. And plenty of riders do swear that they feel better after a massage, so it works for them. But physiologically the effects are so minimal as to be... non-existent. Or not measurable. When you think about it, why would a trained athlete not have an efficient circulatory system? Why would toxins and other waste-products from exercise not be pumped away swiftly from major working muscles like those in the legs? Why would waste linger longer in an athlete, somehow pooling in key areas of great vascular development? Now a non-athlete with fluid retention or some other circulatory problem I could understand, but a highly-trained sports person? I'm open to the evidence, I just haven't seen any that convinces.