Hi Doctor, I Had A Small Pleural Effusion About 4

Hi doctor, I had a small pleural effusion about 4 years ago discovered thought x-ray of my chest. At the time the doctor said the effusion was small that my body would absorb it within a week - which was the case. Apart from short of breath, pain in my chest and back, pain down my lower back (kidneys region) and pain in the left rib region (spleen area). I didn't had any other symptoms such as flu, or headaches, fever, hashes, not even coughing. I never got a diagnosis and 4 years later I still think about it and occasionally still feel pain in my chest. Did two CT scans, one echocardiogram, and nothing was found. Blood tests then showed low lymphocytes (?) - or low something starting with ''L''. My question doctor is if the pleural effusion I had four years ago together with all the other symptoms described above could had been a signed that I'm HIV positive? Was that my seroconversion? Or were those symptoms of AIDS?