Why is mesh reacting weirdly when adding a Solidify modifier or smooth shading? I've been struggling a while to get some sort of a tube/flow conduction for a rotor right, but I get some weird glitches (or I am doing something stupid).

How I made the mesh (maybe it helps to know, so you know where I went wrong):

First I made a cylinder, deleted the bottom and top face. Then I drew a path and made it to a certain shape. After that I use a array modifier on the cylinder and a curve modifier. So after that I was left with a curved tube.

Then I just started to delete some faces to open it up and added some sort of a roof to it, so it would let the water flow in a certain way. 





Problem I am having:

Then I wanted to give it a little bit of thickness, so I used the solidify modifier, but after applying it to the mesh it did not want to do what I want:

 



Also, when I tried to use smooth shading it showed some weird stuff:

 

Link to the photos : https://imgur.com/a/VX4RekM

How do I fix these bumps when I give it a little bit of thickness? And how to fix the weird smooth shading thing?
yes you must have made some bad manipulations but it's hard to tell how it happened. Anyway, you can select all in Edit mode and W > Remove Doubles, with a Merge Distance of 0.02 on the bottom of the left (Tools) panel. Also, recalculate the normals with a ctrlN. Then some isolate vertices will remain and you can delete them: select the main shape with L and invert the selection with ctrli, then X to delete. At last, you have some tris that you could easily replace with quads.