How do I fix the controller?

I bought my titanfall edition controller when it came out (so the 15-day warranty has been expired) and now it is giving me issues. when it comes to my controller, the left trigger seems like it is jammed? I am not exactly sure but the left trigger is not responding completely when I move it upwards and sometimes when I move it upwards and let the stick go, the character (in game) is stuck moving forward. anyone know how to fix this issue? also, what is the specific tool i would need to fix this. any recommendations would be appreciated.