There are many causes for swollen and painful thumb they are osteoarthritis,gout,rheumatoid arthritis,psoriatic arthritis,ankylosing spondylytis etc.we need to know your age and physical examination and some investigations are required to arrive at a diagnosis. tylenol helps in releiving pain and reducing swelling, but long term use will harm gastric tract.general measures like hot compressions and ice pack application and using bigger grip pens for writing,using utensils and garden tools with bigger handles and changing door knobs to latches, using bottle and jar openers etc will be helpful .under lying problem also needs treatment. It is better you consult a qualified physician and get treated immediately.