Suggest Treatment For Severe Left-sided Pain In Leg While Waking Up

I have been having this pain sometimes severe from my left side neck to my left leg but more robust at my lower back side through the buttocks to the left leg for about a week. I woke up one morning and from my left side neck down felt the severe pains as i try to rise up. It was like i have been beaten up or hit on that left side. My muscles were not sore or feel any hit wound, no tenderness of skin or muscles etc. Raising my left leg up was difficult and painful, actually barely able to about a foot high, while bending down to meet halfway - painful. However, once i start moving around, i don t feel any pain unless when i tried to raise the left leg, the area of my back meeting the buttocks area and sometimes down the left leg. I go all day looking like there is no problem until i lay down at night to sleep, then moving around or turning in bed becomes painful and difficult. The symptoms are bafflingly scary, sometimes it is like the left leg is going to buckle. I ve just selected a PCP that i scheduled a physical appmt. with for this Friday. I am concerned about my kidneys as the concentration of this discomforts are pronounced within the left lower back area to the buttocks and the left leg joints area. I will appreciate any lights you can shed on these puzzling conditions. Additional info, in 2012, i had a brachy therapy prostrate cancer proceedure done, could the radiation seeds planted into the prostrate be linked with the effects? Thanks for your information and i hereby acknowledged that you are not giving medical diagnosis rather information that may be relevant with assisting me as i search for treament possibilities. Waoh! am sorry, don have the priviledge of credit cards anymore. However, thanks for the webmd.com and what you do and provide to the at large communities.