Your description most closely matches paronychia, an infection
generally caused by yeasts which get under the cuticle
and inflame the tissue around the nail (what "paronychia" means.) Treatment involves minimizing water exposure and applying a topical anti-yeast cream. Do you ever pick at or rub the nails? If so, please stop.
Most likely, you are correct in your surmise that this condition dos not imply any systemic involvement. Ask a doctor, to be sure.