Strength, numbered VIII (that's eight in Roman numerals)*, is about befriending the ego, and respecting the wildness within, and accepting all emotions as they come. The courage of radical acceptance that things are the way they are, and then using your personal power to make things better, friendlier. Coming to an accord with the good, the bad, the neutral; within and without.
When Strength is in the obstacle position you may be forgetting that you do have sufficient fortitude to weather the storm, but, you do have to be able to bend or you'll snap. Obstinate, controlling, dominating, disrespecting boundaries, misusing your strength to have power over other beings. Power is meant to be shared for equitable living.
When Strength is in the solution position it is an indication that gentle persuasion, calming patience, is needed. Putting anger and unhelpful emotions on the backburner in order to facilitate a better outcome. There is strength in zenning it out, so to speak. Draw on your inner resources to keep moving, keep going, so you can get to the light at the end of the tunnel. Be more kind to yourself. Let your friends love you.
*In some decks Strength is numbered XI (that's 11), and number VIII is Justice.