 [ Symptoms ] is sex painful with bph [ Disease ] i am sorry to hear you are going through this here you are exercising like doctors tell us to and then you have an uncomfortable problem occur it seems a little unfair does not it i am going to recommend you see a doctor about this while several things could cause the symptoms you describe    and i am not a medical doctor myself    your situation sounds an awful lot like it could be a baker is cyst a doctor could tell you for sure baker is cysts are not cancerous or life threatening in any way but they sure can interfere with exercise    and even with activities of daily living your doctor can suggest ways to treat the cyst on your own and if those do not work he or she can perform a small procedure to drain the cyst of course your knee problems could have many other causes such as tendinitis and arthritis your doctor can diagnose the issue with a physical examination and possibly an x ray wishing you well