Alex, you should see if you can find a physiotherapist or massage therapist that does visceral manipulation. Tina (KiX) has taken a lot of courses on this in the past couple of years and has had some incredible results in her treatments.So I have been having this deep abdominal pain for a while and I was starting to worry that it might be a sketchy gallblader, gallstones, or even worse - liver cancer....
It's basically massage of the internal organs, but there's a fair bit more to it. The treatment is based on the idea that all organs have a natural movement, and if that movement gets restricted, it causes issues elsewhere in the body. Pain in the shoulder, for example, could be caused by a restriction in the gall bladder. It sounds a little hokey at first but it's all based on Western science and she's had some pretty crazy results. Just yesterday she treated someone with a knee injury and reduced the swelling by more than an inch by treating her kidneys, she's also fixed shoulder pain by treating the client's gall bladder, stuff like that. And of course, she's had a lot of success in treating people who come in specifically with abdominal symptoms. The nice thing about the treatment is that it's fairly gentle considering that you're having your organs treated.
Check out The Barral Institute - they have a "find a therapist" section where you can find people specialized in visceral manipulation. Tina's treatments have totally changed after taking courses on visceral and nerve manipulation through the Barral Institute.
Your pain very well could be caused by insufficient recovery time after exercise, but it could also be caused by a restriction in one or more of your organs, so it might be worth checking out.