Chevy1998 1500 wont start

I started it up the other morning fine never had problems starting ever. Then after I shut it off it never started again just cranks over constantly. I checked if I was getting fuel and if there was pressure in the line and its good then I pulled the spark plugs and turned it over and they all spark, so I went and bought new ones to see if theres a differnce and they all spark the same also while the plugs where out it spit fumes of gas out of the spark plug wholes so im getting gas to the cylinders and theres spark. Shouldnt it ignite the fuel and fire. I got it to fire up for a second a couple times but just went back to cranking for ever killed the battery trying so had to recharge the battery. Now about 2 months ago after driving the truck wen it would warm up it would all of a sudden not shift into over drive on the highway it would stay n 3rd unless id slow down and also feel a lil hesitant wen id try to give it gas it would take a second to pick up speed but wen I turned the truck off and let it cool down I could start it and drive away and it would shift fine no problems till about 10 or 15 min. Of driving it would start doing it agin do u think this had something to do with it not firing up any more? I read sometihng about if a crankshaft position sensor or ignition control module go out it would crank long with now fire cuz it would lag on the firing time and it also said it could have shifting issues also? So how do I check either of those? And is this my problem or is it something else