Can I Give My Dog Baby Aspirin?

I have a Min Pin, who is 6 1/2 yrs. old. She weighs 10 - 12 lbs. I have noticed when she gets up, she seems stiff and and slightly favors her front end. The stiffness seems to be in either the right or left shoulder. I can't be sure which side she is favoring. She still wants to play and retrieve her squeaky toys. But, when I walk her, she just doesn't seem to be walking soundly. Because it doesn't seem to be chronic, I'm just wondering if it is safe to give a small dose of baby aspirin. Serious answers only. Thank you.