I Have A Very Sedentary Job And Am Obese. I

I have a very sedentary job and am obese. I began having left thigh pain on the lateral side about 6 weeks ago. It felt like a bruise but there is no visual change. The initial bruise-like pain has become more intense and is now quite sore. There is no noticeable swelling or color change but it is quite a bit more painful now. I have, in the past 2 days, begun feeling a little dizzy and noticing a "flutter" to my heart. Should I be concerned?