Pain in lower thigh when bending leg

Hello,
Over the past couple days I've been noticing a dull pain in the back of my thigh,right above the back of my knee, but only feel it when bending my leg. This includes going up stairs. I have a deep purple bruise higher up on the outside of my thigh, but it doesn't seem to hurt in that area. This first thing that came to my mind was blood clot, but what do I know! I don't remember how I would have gotten the bruise and the sore feeling doesn't feel the same as day after exercise soreness. Any thoughts would be great!

Dear ingie179

Your information is very brief. Could you provide us with more information...

is this problem getting worse? is it painful at night? is the ache constant? or only there when you bend your knee all the time?
can you put your finger on the spot that aches or it feels diffuse like you cannot map the area out specifically?
what exercises have you been doing? have you had this problem before?
how did it start? suddenly came up or just gradually crept up on you? over what length of time?
have you tried anything to help with this problem? pain killers? creams?
is there anything that relieves it...?
does it wake you up at night? how does it feel in the morning?
any abnormal color below the part where the aches is?
whats happening in your foot? any discolouration, funny looking skin texture?
anything in your medical history what knowing about or that you feel you want to share with us?
any part of your body behaving the same way...?
any body in your family having this issues?
any weakness of muscles? any loss of sensation?
are you taking any medication? do you react to anything that you can remember?
any pain anywhere else?
suffered any injuries in that part before?
have you spoken to a professional about it? if so what did they say? does this problem stop you from walking? is it only there when you climb the stairs or its there when you squat as well? any swelling? does the area feel warm?
What happens when you lying down on your back or side and you bend your knee? still feel the ache?

more questions might come...

hope to hear from you soon