What Causes Lump On Testicle Along With Pain In Back During Urination?

For over four years, my urine has been dark in colour (I d say the colour of straw). During urination, or at the start my urine turns white lasts several seconds (possibly 6 seconds) then turns back dark in colour. I have a small lump in my left testicle. Any movement causes discomfort, but it is bearable. I also have pain in my left side (just above my hip), when I m about to pass the cloudy urine, my left side hurts, until its passed or it will continue to hurt for several hours afterwards. I seen my GP in regards to the lump they said it was more likely a cyst. When I mentioned about side pain and cloudy urine, they looked puzzled or confused. Quickly dismissing it. I ve no idea what it is nor what I should do. Also, to clarify I m 23 and drink plenty of water throughout the day. So my dark urine couldn t be down to dehydration. Any help or advice would be immensely grateful. Regards Daniel.