Unexplained swelling/pain in left knee

Patient: I have swelling in my left knee and pain when I put weight on the joint. In fact, I believe my entire left leg is slightly swollen, besides the knee. Neither a heat patch nor keeping ice on the area (front, back, sides of knee) helps, altho while putting weight on the knee (standing, walking) is still painful, it is not as painful as it was a couple of days ago. I can at least stand and walk without aid, but pain/swelling is still present. I am 68 YOA, overweight (5’8″, 235#), and do have some arthritis pain in right knee which sustained a small injury several years ago. I also have what I consider minor arthritis pain occasionally in shoulders and elbows and hips, the level of the pain in left knee is greater, and I have not had much problem with the left knee nor swelling in the past. This has occurred in three days’ time. I have not injured the knee in any way. Any Ideas? Tks

Symptoms: See #1. I am not very active, although I do have stairs in my home which I go up and down several times a day. Last Friday, I went grocery shopping and wore 2+” wedge heels for @ an hour. My back, feet, and legs always hurt after such a trip, but the first pain I encountered wasn’t until Monday; I had gone to the post office and returned, was walking with no pain then. The pain/swelling did not begin until later Monday night, and I could hardly walk on Tuesday due to the pain. The ice treatments seem to help with the pain, but swelling is the same. Just FYI, I take no medications except OTC Aleve or equivalent, sleep aids, and Benadryl ( I do have slight allergies). I sometimes have what I call situational high blood pressure due to being overweight (the last time I saw a doctor for the purpose of getting a prescription for phentermine for weight loss, which works very well for me, the doctor would not give it to me; not sure why; tried to give me two other prescription drugs, one of which I filled and took one of; didn’t like how my head felt afterward, so I threw it away). I had taken phentermine several times in past years with successful weight loss and hardly any side effects (only dry mouth).
Anyway, I also have high cholesterol, again due to being overweight. I do not smoke; rarely drink. I try to eat well, altho I’m sure there are ways I could improve. Never had an operation. Never had a broken limb. The most serious health problem I’ve had was having a wisdom tooth pulled with just novocaine. I cannot explain why this knee is bothering me now, if it is not arthritis; the pain/swelling seem indicative of an injury which has not occurred.