If you are experiencing a burning sensation with urination… this is a telltale sign that the fit for girth is too tight.
As Christian points out, the process of Penis Enlargement requires multiple pronged approach with respect to exercises needed to stimulate growth.
To your question, length and girth are not mutually exclusive and have influence over each other. Particularly girth in the flaccid state will be enhanced with gains in length.
You should be including jelqs as a standard practice to engorge the penis with blood for not only gains but overall general health and function of the penis.