Sorry but since I already outed myself as a fashion snob I'm ready to call either bullshit or be mean and say you are either ignorant or stupid on fashion. Either way I will help with some info:
First off, your waist measurement is not the same as a waist measurement on jeans(which is different than that of trousers). Most modern cuts for men sit at the hip, not the waist, so figure out if you are a 31 waist in denim or just your waist in 31 inches.
Second having problems with your legs fitting in the current cut of the waist measurement of the jeans doesnt mean you have monster quads, in fact it is usually the butt that is cut too tight but thats another story. Most fashion brands are built and contructed to fit a model prototype bodystyle. These people tend to be ectomorphs, or tall and lean since the clothes from a sartorial standpoint sit better. example: a small drop(differnence between shoulder and waist) is easier to tailor for than a large and looks more aesthetically pleasing in jackets. So if your legs are tight in the jeans it means the brand you are looking at is tailored for skinny people and you are just normal.
Third, exapnding on the concept that clothes for a brand are built on a universal architype, 90% of the time it will not fit you perfect or off the rack which is why tailors exist.
Fourth, it takes no brains or effort to buy a pair of jeans that fit your legs and then take them to a tailor to alter the length and waist which is what you should do.
Fifth, jeans are supposed to fit slimmer in the thigh and butt, so find a better place for your phone(breast pocket) get a slim and streamlined keychain(car/house/office the rest can be seperate if you dont use everyday) and dont use a George Costanza wallet. Get a card holder(back pocket) and money clip for cash(front pocket) like a man.
Sixth, you are full of shit becasue I am 5'7 with a 31 inch waist and 24 in thighs and have no problem fitting in skinny jeans.