MC34063 heating & low performance problem
You need a resistor in series with the drive signal to the base of the TIP31 transistor - the base/emitter region on the transistor is just a forward biased diode so it will try and clamp the controller output and make it get hot. The current limit resistor that feeds (also) the collector of the internal transistor in the chip is too low to prevent significant (and too large) drive current into the TIP31 base. Alternatively try inserting a resistor in pin 8 - see figure 9, 9a and 9b of data sheet and here's what I mean pictorially: -



Note R2 in the picture.

For the question about the inductor, links to both data sheets are required.