Repetitive strain injuries are very common, either due to excessive computer work, or putting excessive pressure on joints (arms and hands) such as in the case of therapists like myself. One never quite manage to prevent those RSI conditions, however much we try. It will creep up on us in a matter of time.
It is worth bearing in mind that those painful conditions can be alleviated by simple remedies, and I myself have tried them all!
Apart from the use of ice packs on the affected areas, consider using the Essential Oil of Wintergreen for any inflammatory conditions such as tendinitis, arthritis, rheumatism. Apply twice a day on the affected area, after diluting a few drops in a base oil such as almond, coconut or olive oil.
Ointments combining the herbs of comfrey, calendula and hypericum are hugely beneficial as deep penetrating and healing if applied regularly.
Epsom salts, plaisters of castor oil, can help too.
Then, as a good maintenance tip, regular osteopathy, physiotherapy or acupuncture are perfect complements.