What Causes Burning Sensation Before And After Urination?

Hello Doctor, I am experiencing this problem since the past few months. A couple of years back it started with burning sensation before and after urination and a continuous irritation in urethra. I visited my urologist that time and he advised some medication after which it is was okay but the problem reoccurs more often now and occurs more frequently in summer than in winter. My water intake is also very good so was wondering what happened. Now the problem seems to be re occurring more often within a gap of a week/10 days. I am taking medicines for the same and the problem occurs even during medication. I also feel a continuous mild irritation in my penis/urethra and frequent urination. I have been taking medicines prescribed by my urologist since the past 4 weeks but i still feel the problem. Not sure what to do. Could you please advise. Also are there any precautions to be taken in terms of the kind of food or drinks i should/shouldn t take. Regards