Suggest Treatment For Pain In Thighs

My thighs ache for no apparent reason--both of them equally and when I am just lying in bed, walking, or sitting. However, it is greater when I am climbing stairs--almost excrutiating. It is not the pain incurred when I've overworked muscles and pay for it the next day. I'm in generally good health, with mild bursitis. I'm a female construction worker so I'm fairly active but don't have a regular exercise routine. Any help would be greatly appreciated....nancy