Do I have a crooked nose or C shaped nose? If so, how can I straighten it? (Photos)

There are two types of deviated noses: 1) a straight nose, but the complete axis is off to one side, and 2) a C-shaped deviated nose. The most common reasons for the latter are either trauma to the nose (a side-punch against a nose) or a severely deviated nasal Septum, that results in a C-shape. It is very likely that a severely deviated Septum is the main reason for all your issues. The Septum creates a curve, pushing the tip of your nose to the left and blocking your right nasal cavity (hence the constant breathing issues on your right side). The most likely reasons you did not see any of this during puberty are since everything looked alright, you did not pay too much attention to your nose, and as the nose was growing, the septum deviated and created the c-shaped deviation. 
Greg Bran MD PhD
Dual Board certified Facial Plastic Surgeon

You have both a functional and a cosmetic issue so make sure your surgeon is a board certified Plastic Surgeon or Ear Nose and Throat Surgeon with experience correcting both.  It is impossible to know from your pictures exactly what is causing the obstruction to your breathing, but my guess is you may have both a septal deviation and weak support of the nose.  Again, your surgeon will have to do a full evaluation and formulate a plan specific to your particular findings and goals.  Good luck