Hello and welcome to HCM, Lump on upper part of thigh is most probably due to soft tissue swelling. Associated muscle pain suggests a swelling arising from muscles. A clinical assessment of the swelling is required. Imaging of the upper thigh is also required to know the origin and extent of the swelling. After imaging study, aspiration cytology of the swelling is required. In aspiration cytology, cells are aspirated, spread on slide and stained with appropriate stains. By studying the stained cells, the origin and nature of the swelling can be assessed and thus appropriate treatment can be instituted. Thanks and take care Dr Shailja P Wahal